Mesogenic polycyanates and thermosets thereof

ABSTRACT

Novel polycyanate and polycyanamide compositions containing one or more rodlike mesogenic moieties, when cured, result in products having improved properties.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 08/091,460 filed Jul. 13,1993, now abandoned, which is a continuation of application Ser. No907,993, filed Jul. 2, 1992, now abandoned, which is acontinuation-in-part of application Ser. No. 07/746,527 filed Aug. 16,1991, now abandoned which is a continuation-in-part of now abandoned,application Ser. No. 07/380,938 filed Jul. 17, 1989, all of which areincorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention concerns polycyanates (polycyanamides) containingone or more rodlike mesogenic moieties.

BACKGROUND OF THE INVENTION

Aromatic polycyanates which are thermosettable to polytriazines areknown, for example, from U.S. Pat. Nos. 3,448,079; 3,553,244; 3,694,410;3,740,348; 3,755,402; 4,094,852 and 4,097,455. Said polytriazinespossess excellent heat resistance, however, an improvement in theirmechanical properties, especially tensile and flexural strength, tensileand flexural modulus and tensile elongation while maintaining or evenincreasing glass transition temperature, would be desirable. The presentinvention provides a method for improving one or more of theaforementioned properties by incorporation into the polymer chains ofthe polytriazines one or more rodlike mesogenic structure(s).Incorporation of said rodlike mesogenic structures can lead to amolecular level ordering of the polytriazine thermoset thereof. Thepresent invention also provides polymerizable mixtures containing one ormore of the polycyanates (polycyanamides) containing rodlike mesogenicstructure(s) with, for example, one or more polycyanates(polycyanamides) which do not contain rodlike mesogenic moieties, epoxyresins, polymaleimides, polyamines, polyphenols, polymerizableethylenically unsaturated compounds, compounds which simultaneouslycontain both a cyanate or cyanamide group and a polymerizableethylenically unsaturated group, compounds which simultaneously containboth a 1,2-epoxide group and a polymerizable ethylenically unsaturatedgroup, compounds which simultaneously contain both a maleimide group anda cyanate or cyanamide group and materials which contain one or morerodlike mesogenic structure(s) and an average of one cyanate orcyanamide group per molecule. The thermoset compositions prepared fromthe aforementioned polymerizable mixtures typically possess improvementsin physical and mechanical properties relative to those thermosetcompositions prepared using polycyanates (polycyanamides) which do notcontain rodlike mesogenic structure(s).

Certain of the polycyanates containing rodlike mesogenic structure(s)exhibit novel thermally induced self-curing behavior at onsettemperatures much lower than those encountered with the polycyanateswhich do not contain rodlike mesogenic structure(s). Two distinctvariations of this modified curing behavior are provided: As a specificexample, when the azomethine group (--CH═N--) is present as a rodlikemesogenic structure, it can lower the onset temperature to curingwithout participating in the formation of the curing structure of thethermoset product. As a second example, when the secondary amide group(--NH--CO--) is present, it too can lower the onset temperature tocuring, but appears to participate in the formation of the curingstructure of the thermoset product via reaction of the amide proton.When used as a component in the polymerizable mixtures of the presentinvention, these same polycyanates can often be used to reduce the onsettemperature required to cure (thermoset) said mixture.

SUMMARY OF THE INVENTION

The present invention pertains to polycyanate or polycyanamidecompositions containing one or more rodlike mesogenic moieties,particularly those represented by the following Formulas I, II, III orIV ##STR1## wherein at least about 80 percent of the --A-- linkages, thedirect bond in Formula III and the Y groups are in the para positionwith respect to each other; each Y is independently a --O--C.tbd.N or a--NR¹ --C.tbd.N group; each A is independently --CR¹ ═CR¹ --,--C.tbd.C--, --N═N--, --CR¹ ═N--, --O--CO--, --NR¹ --CO--, --CR¹═N--N═CR¹ --, --CR¹ ═CR¹ --CO--, --CO--O--, --CO--NR¹ --, --CO--CR¹ ═CR¹--, --CR¹ ═CR¹ --O--CO--(CH₂)_(n') --, --N═CR¹ --, --(CH₂)_(n')--CO--O--CR¹ ═CR¹ --, --CR¹ ═CR¹ --O--CO--, --CO--O--CR¹ ═CR¹ --,--CO--O--N═CR¹ --, --CR¹ ═N--O--CO-- , --CR¹ ═CR¹ --CO--O--, --CO--S--,--O--CO--CR¹ ═CR¹ --, --CR¹ ═CR¹ --CO--O--(CH₂)_(n') --, --S--CO--,--(CH₂)_(n') --O--CO--CR¹ ═CR¹ --, --CHR¹ --CHR¹ --CO--O--,--O--CO--CHR¹ --CHR¹ --, --C.tbd.C--C.tbd.--C--, --CR¹ ═CR¹ --CR¹ ═CR¹--, --CO--NR¹ --NR¹ --CO--, ##STR2## A' is a divalent hydrocarbyl grouphaving from 1 to about 10, preferably from 1 to about 4, carbon atoms;each A" is independently an alkylene group having from 1 to about 10carbon atoms, preferably from 1 to about 4 carbon atoms, a direct bond,--O--, --CO--, --S--, --S--S--, --SO--, --SO₂ -- or --O--CO--O--; eachA¹ is independently a --CO--, --O--CO--, --CO--O--, --CO--NR¹ --, or--NR¹ --CO-- group; each

R is independently hydrogen or a hydrocarbyl or hydrocarbyloxy grouphaving from 1 to about 10, preferably from 1 to about 4, carbon atoms, ahalogen atom, preferably chlorine or bromine, a nitro group, a nitrilegroup, a phenyl group or a --CO--R¹ group; each R¹ is independentlyhydrogen or a hydrocarbyl group having 1 to about 3 carbon atoms; v hasa value of one or two;

n has a value of zero or one; n' has a value from 1 to about 6,preferably 1 to about 3; p has a value from 1 to about 30, preferablyfrom 1 to about 3; and not including 4,4'-dicyanatostilbene,4,4'-dicyanamidoazobenzene, 4,4'-dicyanamidobenzanilide,4,4'-dicyanamidophenyl benzoate, dicyanates of the diphenol esters ofterephthalyl chloride and bisphenol A, 4,4'-dihydroxydiphenyl, anddicyanates represented by the following formulas ##STR3## wherein Ar isan aromatic radical selected from the group consisting of 1,4-benzene,1,4-naphthalene, 1,5-naththalene, 2,6-naphthalene, 2,7-naphthalene,4,4'-biphenyl, 4,4'-diphenylalkylene radicals and can possess anynonactive hydrogen-containing substituent(s) which do not removemesogenicity. The aromatic rings can also contain one or moreheteroatoms such as N, O or S and the like.

The term mesogen is defined by R. A. Weiss (ed.) and C. R. Ober (ed.) inLiquid-Crystalline Polymers, ACS Symposium Series 435 (1989) on page 2:"The rigid unit responsible for the liquid crystalline behavior isreferred to as the mesogen." and "Liquid crystalline order is aconsequence solely of molecular shape anisotropy, such as found in rigidrod-shaped molecules . . . ". Further definition of the term mesogen maybe found in Polymeric Liquid Crystals, Alexandre Blumstein (ed.) (1983)on pages 2-3 and in Polymeric Liquid crystals, A. Ciferri, W. R.Krigbaum and Robert B. Meyer (eds.) (1982) on pages 5-9, both of whichare incorporated herein by reference.

Thus, while the dicyanate, 1,4-bis(p-cyanatophenyl)cyclohexane ismesogenic and thus a composition of the present invention,1,1-bis(p-cyanatophenyl)cyclohexane is not mesogenic and is thus not acomposition of the present invention, due to the 1,1-disubstitution ofthe cyclohexane ring which leads to a highly bent structure. Thedicyanates of 1,4-bis(4'-hydroxyphenyl)propyl)benzene,2,2-bis(3',5'-dimethyl-4'-hydroxyphenyl)propane,2,2-bis(4'-hydroxyphenyl-1,1,1,3,3,3-hexafluoropropane) and9,9-(bis(4-hydroxyphenyl)fluorene are likewise not compositions of thepresent invention because they do not possess the proper molecular shapeanisotropy required for mesogenicity to exist.

Woo and Murray in U.S. Pat. No. 4,751,323, which is incorporated hereinby reference in its entirety, disclose polyaromatic cyanates of thegeneral formula

    N.tbd.C--O--Ar-polycyclic aliphatic-Ar--O--C.tbd.N

where Ar refers to any radical containing an aromatic group and maypossess any nonactive hydrogen-containing substituent(s). The polycyclicaliphatic radicals include ##STR4## wherein D¹ is a C₁₋₅ alkyl group andD² is --CH₂ --, --S--, --SO--, or --SO₂ --. These compounds do notpossess the proper molecular shape anisotropy for mesogenicity to existand are thus not compositions of the present invention. As a specificexample, 1,4-bis(p-cyanatophenyl) substituted ##STR5## possesses theproper molecular shape anisotropy to be mesogenic and is thus acomposition of the present invention, while 1,4-bis(p-cyanatophenyl)substituted ##STR6## does not, and is thus not a composition of thepresent invention.

The term hydrocarbyl as employed herein means any aliphatic,cycloaliphatic, aromatic, aryl substituted aliphatic or cycloaliphatic,or aliphatic or cycloaliphatic substituted aromatic groups. Thealiphatic or cycloaliphatic groups can be saturated or unsaturated. Whenapplied to the A' group of Formula III, the hydrocarbyl group can alsocontain one or more heteroatoms selected from N, O, S and the like.Likewise, the term hydrocarbyloxy means a hydrocarbyl group having anoxygen linkage between it and the carbon atom to which it is attached.

Another aspect of the present invention pertains to compositionsresulting from curing (thermosetting) one or more of the polycyanates orpolycyanamides containing one or more rodlike mesogenic moieties,optionally in the presence of one or more curing agents or curingcatalysts.

Another aspect of the present invention is directed to polymerizablecompositions comprising a mixture containing

(A) at least one thermosettable polycyanate or polycyanamide containingone or more rodlike mesogenic moieties; and

(B) at least one of

(1) at least one polycyanate or polycyanamide which does not containrodlike mesogenic structures;

(2) at least one epoxy resin;

(3) at least one polymaleimide;

(4) at least one polyamine;

(5) at least one polyphenol;

(6) at least one compound containing one or more polymerizableethylenically unsaturated group(s);

(7) at least one compound which contains in the same molecule both acyanate or cyanamide group and a polymerizable ethylenically unsaturatedgroup;

(8) at least one compound which contains in the same molecule both a1,2-epoxide group and a polymerizable ethylenically unsaturated group;

(9) at least one compound which contains in the same molecule both amaleimide group and a cyanate group;

(10) at least one compound which contains one or more rodlike mesogenicmoieties and only one cyanate or cyanamide group per molecule;

(11) at least one prepolymer of any of the aforesaid components (1)through (10) or any combination of any two or more of said components;or

(12) a mixture of any two or more of components (1) through (11) in anyproportion and any combinations, with the proviso that component (A) mayinclude 4,4'-dicyanatostilbene (Formula I, R=--H, Y=--O--C.tbd.N,A=--CH═CH--) if components (B-4) or (B-5) are not used and with theproviso that component (A) may include 4,4'-dicyanamidoazobenzene(Formula I, R=--H, Y=--NH--C.tbd.N, A=--N═N--),4,4'-dicyanamidobenzanilide (Formula I, R=--H, Y=--NH--C.tbd.N,A=--NH--CO--) or 4,4'-dicyanamidophenylbenzoate (Formula I, R=--H,Y=--NH--C.tbd.N, A=--CO--O--) if components (B-3) or (B-4) are not usedand with the proviso that component (A) may include the compositions ofFormula IV where R is --H or --CH₁₃ , n= 1, Y=--O--C.tbd.N, A" is ashereinbefore defined, where both A groups may simultaneously be--O--CO-- and with the proviso that component (A) can include the1,4-bis(p-cyanotophenyl)bicyclo[2.2.2]-octanes (Formula I, R=--H, ahydrocarbyl or hydrocarbyloxy group having from 1 to about 10 carbonatoms, or halogen atoms a nitro groups a nitrile group, a phenyl groupor a --CO--R¹ group where R¹ is hydrogen or a hydrocarbyl group having 1to about 3 carbon atoms; Y=--O--C.tbd.N; ##STR7## where n=0, v=2 and R¹=--H if component (B-1) is not used and with the proviso that component(A) can include the 1,4-bis(p-cyanatophenyl)bicyclo[2.2.2]oct-2-enes(Formula I, R=--H, a hydrocarbyl or hydrocarbyloxy group having from 1to about 10 carbon atoms, a halogen atom, a nitro group, a nitrilegroup, a phenyl group or a --CO--R¹ group where R¹ is hydrogen or ahydrocarbyl group having from 1 to about 3 carbon atoms; Y=--O--C.tbd.N;A= ##STR8## where n=0, v=2 and R¹ =--H if component (B-1) is not used.

Another aspect of the present invention pertains to compositionsresulting from polymerizing the aforementioned polymerizablecompositions.

A further aspect of the present invention pertains to products resultingfrom orienting any of the aforementioned polymerizable compositions.

The term prepolymers as employed herein means that the compound has beenhomopolymerized or cooligomerized or interoligomerized orhomopolymerized or copolymerized or interpolymerized so as to cause anincrease in molecular weight, but not to such an extent that the producthas become cured, i.e. insoluble and infusible, but rather, the productis capable of being subsequently cured to an insoluble, infusible state.

These compounds can also contain substituent groups such as saturatedaliphatic hydrocarbon, unsaturated aliphatic hydrocarbon, halogensincluding chlorine bromine, fluorine, iodine, nitro, nitrile, and thelike. Likewise, the hydrocarbon substituent groups can also besubstituted with such halogens including chlorine bromine, fluorine,iodine, nitro, nitrile, and the like. Also, these compounds can bespecifically free of any one or more of such substituent groups andlikewise the substituted hydrocarbons can be specifically free of anyone or more of such substituent groups. Further, such compounds andsubstituted hydrocarbons can contain any substituent group notspecifically enumerated herein. Likewise, the compounds and substitutedhydrocarbons can be free of any substituent group not specificallyenumerated herein.

The present invention may suitably comprise, consist of, or consistessentially of, the aforementioned components.

The invention illustratively disclosed herein suitably may be practicedin the absence of any component which is not specifically disclosed orenumerated herein and any of the compounds may contain or be free of anysubstitutent not specifically named herein.

DETAILED DESCRIPTION OF THE INVENTION

PREPARATION OF THE POLYCYANATES OR POLYCYANAMIDES CONTAINING ONE OR MORERODLIKE MESOGENIC MOIETIES

The polycyanates or polycyanamides of the present invention are preparedby reacting one or more of the polyphenols, polyamines or aminophenolscontaining one or more rodlike mesogenic moieties with a stoichiometricquantity or a slight stoichiometric excess (up to about 20 percentexcess) of a cyanogen halide per --OH or --NHR¹ group in the presence ofa stoichiometric quantity or a slight stoichiometric excess (up to about20 percent excess) of a base compound per --OH or --NHR¹ group and inthe presence of a suitable solvent.

Reaction temperatures of from about -40° C. to about 60° C. areoperable, with reaction temperatures of -15° C. to 10° C. beingpreferred. Reaction times can vary substantially, for example, as afunction of the reactants being employed, the reaction temperature,solvent(s) used, the scale of the reaction, and the like, but aregenerally between 15 minutes and 4 hours, with reaction times of 30minutes to 90 minutes being preferred.

Suitable polyphenols, polyamines or aminophenols which can be employedherein to prepare the polycyanates or polycyanamides containing one ormore rodlike mesogenic moieties include, for example, any compound whichhas an average of more than one aromatic hydroxyl group, aromaticprimary or secondary amino group or a combination of said hydroxyl andamino groups per molecule and include, for example, those represented bythe Formulas V, VI, VII or VIII ##STR9## wherein at least about 80percent of the --A-- linkages in Formulas V, VI and VIII and the directbond between the two aromatic rings in Formula VII and the Y¹ groups arein the para position with respect to each other; each Y¹ isindependently a --OH or --NHR¹ group; each A, A', A", A¹, R, R¹, v, n,n' and p are as hereinbefore defined. The aromatic rings can alsocontain one or more heteroatoms selected from N, O, S and the like.

Particularly suitable polyphenols are4,4'-dihydroxy-alpha-methylistilbene, 4,4'-dihydroxychalcone,4,4-dihydroxydiphenylacetylene, 4,4'-dihydroxydiphenylazomethine,4,4'-dihydroxyazobenzene, 4,4'-dihydroxyazoxybenzene,4,4'-bis(4-hydroxyphenoxy)diphenyl, 4,4'-dihydroxy-alpha-cyanostilbene,4,4'-dihydroxybenzanilide, 4-hydroxyphenyl-4-hydroxybenzoate, ##STR10##

Particularly suitable polyamines are 4,4'-diaminostilbene,4,4'-diamino-alpha-methylstilbene, 4,4'-diaminodiphenylacetylene,4,4'-diamino-alpha-cyanostilbene, 4,4'-bis(4-aminophenoxy)diphenyl,4,4'-diaminodiphenylazomethine, 4,4'-diamino-3,3'-dichlorobenzanilide,4,4'-diamino-3,3'-dichloroazobenzene, ##STR11##

Particularly suitable aminophenols are 4-amino-4'-hydroxystilbene,4-amino-4'-hydroxy-alpha-methylstilbene,4-amino-4'-hydroxy-alpha-cyanostilbene, 4-amino-4'-hydroxybenzanilide,mixtures thereof and the like.

Suitable cyanogen halides include cyanogen chloride and cyanogenbromide. Alternately, the method of Martin and Bauer described inOrganic Synthesis, volume 61, pages 35-68 (1983) published by John Wileyand Sons can be used to generate the required cyanogen halide in situfrom sodium cyanide and a halogen such as chlorine or bromine.

Suitable base compounds include both inorganic bases and tertiary aminessuch as sodium hydroxide, potassium hydroxide, trimethylamine,triethylamine, mixtures thereof, and the like. Triethylamine is mostpreferred as the base.

Suitable solvents for the cyanation reaction include water, aliphaticketones, chlorinated hydrocarbons, aliphatic and cycloaliphatic ethersand diethers, aromatic hydrocarbons, mixtures thereof and the like.Acetone methylethylketone, methylene chloride or chloroform areparticularly suitable as the solvent.

CURING OF THE POLYCYANATES OR POLYCYANAMIDES CONTAINING ONE OR MORERODLIKE MESOGENIC MOIETIES

The polycyanates or polycyanamides containing one or more rodlikemesogenic structure(s) are cured (thermoset) by heating from about 50°C. to about 400° C., preferrably by heating from 100° C. to 250° C.,optionally in the presence of a suitable catalyst. Suitable catalystsinclude, for example, acids, bases, salts, nitrogen and phosphoruscompounds, such as for example, Lewis acids such as AlCl₃, BF₃, FeCl₃,TiCl₄, ZnCl₂, SnCl₄ ; protonic acids such as HCl, H₃ PO₄ ; aromatichydroxy componds such as phenol, p-nitrophenol, pyrocatechol,dihydroxynaphthalene; sodium hydroxide, sodium methylate, sodiumphenolate, trimethylamine, triethylamine, tributylamine,diazabicyclo[2.2.2]-octane, quinoline, isoquinoline,tetrahydroisoquinoline, tetraethylammonium chloride, pyridine-N-oxide,tributyl phosphine, zinc octoate, tin octoate, zinc naphthenate, cobaltnaphthenate, cobalt octoate, cobalt acetylacetonate and the like. Alsosuitable as catalysts are the metal chelates such as, For example, thechelates of transition metals and bidentate or tridentate ligands,particularly the chelates of iron, cobalt, zinc, copper, manganese,zirconium, titanium, vanadium, aluminum and magnesium. These and otheroperable catalysts are disclosed in U.S. Pat. Nos. 3,694,410 and4,094,852 which are incorporated herein by reference in their entirety.Cobalt naphthenate, cobalt octoate and cobalt acetylacetonate are mostpreferred as the catalysts. The quantity of catalyst used, if any,depends on the structure of the particular catalyst, the structure ofthe polycyanate or polycyanamide being cured, the cure temperature, thecure time, and the like. Generally, catalyst concentrations of fromabout 0.001 to about 2 percent by weight are preferred.

B-staging or prepolymerization of the compositions of the polycyanatesor polycyanamides of the present invention can be accomplished by usinglower temperatures and/or shorter curing times. Curing of the thusformed B-staged (prepolymerized) resin can then be accomplished at alater time or immediately following B-staging (prepolymerization) byincreasing the temperature and/or curing time.

The cured (thermoset) products prepared from the polycyanates orpolycyanamides containing rodlike mesogenic structure(s) possess thecyanate group homopolymerization structure ##STR12## or the cyanamidegroup homopolymerization structure unless other functionalities arepresent in the polycyanate or polycyanamide that participate in thecuring process. Such a case occurs in the curing of4,4'-dicyanatobenzanilide where participation of the secondary amidehydrogen in the curing process leads to the formation of additionalcuring structure(s).

POLYCYANATES OR POLYCYANAMIDES WHICH DO NOT CONTAIN RODLIKE MESOGENICMOIETIES AND WHICH CAN BE EMPLOYED IN THE CURABLE AND CURED COMPOSITIONS

Suitable polycyanates or polycyanamides which do not contain rodlikemesogenic structures and which can be employed to prepare thepolymerizable mixtures of the present invention include, for example,those represented by the following Formulas IX, X, XI and XII ##STR13##wherein Y, A" and n are as hereinbefore defined; each A² isindependently an alkylene group having from 1 to about 10, preferablyfrom 1 to about 4 carbon atoms or a ##STR14## each R' is independentlyhydrogen, a hydrocarbyl or hydrocarbyloxy group having from 1 to about10, preferably 1 to about 4 carbon atoms, a halogen, preferably chlorineor bromine, a phenyl group, a --O--C.tbd.N group, or a --NR¹ --C.tbd.Ngroup; each R" is independently hydrogen, a hydrocarbyl orhydrocarbyloxy group having from 1 to about 10, preferably 1 to about 4carbon atoms, a halogen, preferably chlorine or bromine, or a phenylgroup; p' has a value from zero to about 100, preferably from zero toabout 30; p" has a value of from zero to about 10, preferably from zeroto 3 and m has a value of from about 0.001 to about 6, preferably fromabout 0.01 to about 3. The aromatic rings can also contain one or moreheteroatoms selected from N, O, S and the like.

Suitable polycyanates or polycyanamides which do not contain rodlikemesogenic structures represented by Formulas IX, X, XI and XII include,for example, bisphenol A dicyanate, the dicyanates of4,4'-dihydroxydiphenyl oxide, resorcinol, hydroquinone,4,4'-thiodiphenol, 4,4'-sulfonyldiphenol, 3,3',5,5'-tetrabromobisphenolA, 2,2',6,6'-tetrabromobisphenol A, 2,2'-dihydroxy-diphenyl,3,3'-dimethoxybisphenol A, 4,4'-dihydroxydiphenylcarbonate,dicyclopentadiene diphenol, 1,1-bis(p-hydroxyphenyl)cyclohexane,4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl methane,tricyclopentadiene diphenol, the tricyanate oftris(hydroxyphenyl)methane, the tetracyanate of2,2',4,4'-tetrahydroxydiphenyl methane, the polycyanate of a phenolformaldehyde condensation product (novolac), the polycyanate of adicyclopentadiene and phenol condensation product, the dicyanamide of4,4'-diaminodiphenyl methane, the cyanate/cyanamide of p-aminophenol,and the like.

The polycyanates or polycyanamides which do not contain rodlikemesogenic structures are prepared using the corresponding polyphenol,polyamine or aminophenol precursor and the previously describedcyanation (cyanamidation) chemistry. As a specific process unique to thepresent invention, mixtures of one or more polyphenols, polyamines oraminophenols which do not contain rodlike mesogenic structures with oneor more polyphenols, polyamines or aminophenols which contain one ormore rodlike mesogenic structure(s) may be cyanated (cyanamidated) toprovide a polymerizable mixture of the present invention.

EPOXY RESINS WHICH CAN BE EMPLOYED IN THE CURABLE AND CURED COMPOSITIONS

Suitable epoxy resins which can be employed to prepare the polymerizablemixtures of the present invention include materials having an average ofmore than one vicinal epoxide group per molecule, such as, for example,the epoxy resins represented by the following Formulas XIII, XIV, XV,XVI, XVII, XVIII, XIX, XX, XXI, XXII ##STR15## wherein A, A², A', A", R,R¹, R", m, p and n are as hereinbefore defined; each R³ is independentlyhydrogen, or a hydrocarbyl or halohydrocarbyl group having from 1 toabout 6, preferably 1 to about 2 carbon atoms; Q is a direct bond, --CH₂--S--CH₂ --, --(CH₂)_(n") --, or ##STR16## m' has a value of from zeroto about 30, preferably from about zero to about 5; m" has a value from1 to about 10, preferably from about 1 to about 4 and n" has an averagevalue from about 1 to about 10. The aromatic rings can also contain oneor more heteroatoms selected from N, O, S and the like.

Particularly suitable epoxy resins represented by Formulas XIII, XIV,XV, XVI, XVII, XVIII, XIX, XX, XXI and XXII are the diglycidyl ethers ofresorcinol, hydroquinone, dihydroxydiphenyl methane, bisphenol A,3,3',5,5'-tetrabromobisphenol A, 4,4'-sulfonyldiphenol,4,4'-thiodiphenol, 4,4'-dihydroxydiphenyl oxide,4,4'-dihydroxybenzophenone, 2,2'-dihydroxydiphenyl, dicyclopentadienediphenol, tricyclopentadiene diphenol, 4,4'-dihydroxydiphenyl,4,4'-dihydroxystilbene, 4,4'-dihydroxy-alpha-methylstilbene,4,4'-dihydroxy-alpha-cyanostilbene, 4,4'-dihydroxychalcone,4,4'-dihydroxydiphenylacetylene, 4,4'-dihydroxydiphenylazomethine,4,4'-dihydroxyazobenzene, 4,4'-bis(4-hydroxyphenoxy)diphenyl,4,4'-dihydroxybenzanilide, ethylene glycol, thiodiglycol, diethyleneglycol, dipropylene glycol, polypropylene glycol, polyethylene glycol,1,4-cyclohexanediol, dibutylene glycol, the advancement reaction productof the diglycidyl ether of bisphenol A and bisphenol A, the advancementreaction product of the diglycidyl ether of4,4'-dihydroxy-alpha-methylstilbene and4,4'-dihydroxy-alpha-methylstilbene, the triepoxide of p-aminophenol,the tetraepoxide of 4,4'-diaminodiphenyl methane, the triglycidyl etherof tris(hydroxyphenyl)methane, the tetraglycidyl ether of2,2',4,4'-tetrahydroxydiphenyl methane, the polyglycidyl ether of aphenolformaldehyde condensation product (novolac), the polyglycidylether of a dicyclopentadiene or oligomer thereof and phenol or halogenor alkyl substituted phenol condensation product and the like.

The aforementioned epoxy resins can be prepared by reaction of apolyphenol (polyamine, aminophenol, polyalkylene glycol) with anepihalohydrin and a basic acting material. Said reaction generallyinvolves two distinct steps: coupling reaction of the epihalohydrin andpolyphenol to provide a halohydrin intermediate and dehydrohalogenationreaction of the halohydrin intermediate to provide the glycidyl etherproduct. Suitable catalysts and reaction conditions for preparing epoxyresins are described in the Handbook of Epoxy Resins by Lee and Neville,McGraw-Hill (1967) which is incorporated herein by reference.

POLYMALEIMIDES FOR USE IN THE CURABLE AND CURED COMPOSITIONS

Suitable polymaleimides which can be employed to prepare thepolymerizable mixtures of the present invention include, for example,those represented by the Formulas ##STR17## wherein A, A², A', A", R,R¹, R", m, n and p are as hereinbefore defined and Q¹ is a divalenthydrocarbyl group having from 2 to about 12 carbon atoms and may belinear or branched aliphatic, cycloaliphatic or polycycloaliphatic. Thearomatic rings can also contain one or more heteroatoms selected from N,O, S and the like.

Particularly suitable polymaleimides represented by Formulas XXIII,XXIV, XXV, XXVI, XXVII, XXVIII, XXIX and XXX areN,N'-ethylenebismaleimide, N,N'-ethylenebis(2-methylmaleimide),N,N'-hexamethylenebismaleimide, N,N'-(oxydi-p-phenylene)bismaleimide,N,N'-(methylenedi-p-phenylene)maleimide,N,N'-(methylenedi-p-phenylene)bis(2-methylmaleimide),N,N'-(thio-di-p-phenylene)bismaleimide,N,N'-(sulfonyldi-m-phenylene)bismaleimide,N,N'-(isopropylidenedi-p-phenylene)bismaleimide, polymethylenepolyphenylene polymaleimides, the bismaleimide of 4,4'-diaminostilbene,the bismaleimide of 4,4'-diaminobenzanilide and the like.

The polymaleimides can be prepared by reacting a stoichiometric quantityof a maleic anhydride per amine group with a polyamine in the presenceof a suitable solvent, such as, for example, aromatic hydrocarbons,chlorinated hydrocarbons or N,N-dimethylformamide. The polymaleamic acidresulting from reaction of a maleic an hydride and a polyamine may beisolated and dehydrated to the desired polymaleimide. Alternately, thereaction may be performed in a single continous step. Detailedprocedures for preparing polymaleimides can be found in U.S. Pat. Nos.2,444,536; 2,462,835, and Journal of Polymer Science: Part A: PolymerChemistry, Vol. 27, pages 375-388 (1989) which are incorporated hereinby reference.

POLYAMINES SUITABLE FOR USE IN THE CURABLE AND CURED COMPOSITIONS

Suitable polyamines which can be employed to prepare the polymerizablemixtures of the present invention, include those containing one or moreof the rodlike mesogenic structure(s) already described herein, as wellas any of the other known polyamines which do not contain rodlikemesogenic structures. Typical representatives of said polyamines free ofrodlike mesogenic structures include 1,4-diamino-butane,1,6-hexanediamine, 1,12-diaminododecane,2-methyl-4-ethyl-1,8-diaminooctane, 1,4-diamino-cyclohexane,4,4'-diaminodiphenyl methane, 1,4-diaminobenzene,tris(aminophenyl)methane, anilineformaldehyde condensation products andthe like.

POLYPHENOLS SUITABLE FOR USE IN THE CURABLE AND CURED COMPOSITIONS

Suitable polyphenols which can be employed to prepare the polymerizablemixtures of the present invention, include those containing one or moreof the rodlike mesogenic structure(s) already described herein as wellas any of the other known polyphenols which do not contain rodlikemesogenic structures. Typical representatives of said polyphenols freeof mesogenic or rodlike structures include resorcinol,4,4'-sulfonyldiphenol, 4,4'-dihydroxydiphenyl oxide,tris(hydroxyphenyl)methane, phenolformaldehyde condensation products andthe like.

POLYMERIZABLE UNSATURATED MONOMERS SUITABLE FOR USE IN THE CURABLE ANDCURED COMPOSITIONS

Suitable compounds containing one or more polymerizable ethylenicallyunsaturated group(s) which can be employed to prepare the polymerizablemixtures of the present invention include both those containing one ormore rodlike mesogenic structure(s) and those free of said structures.

Suitable polymerizable ethylenically unsaturated monomers containing oneor more rodlike mesogenic moieties are cataloged by Alexandre Blumsteinin Liquid Crystalline Order in Polymers, published by Academic Press,New York (1978) on pages 105-140; Mesomorphic Order in Polymers andPolymerization in Liquid Crystalline Media published by AmericanChemical Society (ACS Symposium Series 74), Washington, D.C. (1978) onpages 56-70; and N. A. Plate and V. P. Shibaev in Comb-Shaped Polymersand Liquid Crystals published by Plenum Press, New York (1987) on pages1-415, V. Percec, et. al., Polymer Bulletin, 17, pages 347-352 (1987);R. Duran and P. Gramain, Makromol. Chem., 188, pages 2001-2009 (1987);A. M. Mousa, et. al., Polymer Bulletin, 6, pages 485-492 (1982); H.Finkelmann, et. al., Makromol. Chem., 179, pages 829-832 (1978); M.Portugall, et. al., Makromol. Chem., 183, pages 2311-2321 (1982) andU.S. Pat. Nos. 4,637,896 and 4,614,619, all of which are incorporatedherein by reference. Suitable polymerizable ethylenically unsaturatedmonomers containing one or more rodlike mesogenic moieties per moleculeare represented by the Formulas XXXI or XXXII:

    M--Q.sup.2                                                 Formula XXXI

    M--(Q.sup.3).sub.n --R.sup.4 --Q.sup.2                     Formula XXXII

wherein n and R¹ are as hereinbefore defined, M is a group containingtwo or more aromatic rings bridged by a rigid central linkage, R⁴ is adivalent hydrocarbon group having from one to about 12 carbon atoms andmay be linear, branched, cyclic, aromatic or a combination thereof andmay be substituted with one or more inert groups, such as, for example,a methoxy group, or may contain one or more inert heteroatom containinglinkages, such as, for example, an ether linkage; Q³ is --O--, --NR¹ --,--S--, --O--CO--, --CO--O--, --NR¹ --CO--, --CO--NR¹ --, --CO--,--O--CO--O--, --S--CO--, --CO--S--, --NR¹ --CO--O--, --O--CO--NR¹ --,--NR¹ --CO--NR¹ --, and Q² is a polymerizable ethylenically unsaturatedgroup. As a class, these monomers generally contain a --CH═CH₂, allyl,methallyl, propenyl, isopropenyl, acrylate or methacrylate group as thepolymerizable ethylenically unsaturated group and a linear divalentaliphatic, aliphatic ether, aliphatic polyether, aliphatic thioether orcycloaliphatic flexible spacer connecting the polymerizableethylenically unsaturated group and the rodlike mesogenic group(s)through a heteroatom linkage. Typical rodlike mesogenic groups includethose wherein two or more aromatic rings are bridged by a rigid centrallinkage wherein said rigid central linkage is required to bridge thearomatic rings to provide at least about 80 percent para substitution.The aromatic rings can be inertly substituted, however, unsubstitutedaromatic rings which maximize the molecular aspect ratio are preferred.Also preferred is a single inert substituent in the para position on thering not connected to the polymerizable ethylenically unsaturated group(either directly or via a flexible spacer). This type of substituent canbe used to enhance the molecular aspect ratio. Typical of these inertsubstituents are CH₃ O--, Cl--, NO₂ --, --C.tbd.N and the like. Thearomatic rings can also contain one or more heteroatoms selected from N,O, S and the like. Typical rigid central linkage groups for bridging thearomatic rings include, for example, a direct bond, --CR¹ ═CR¹ --,--C.tbd.C--, --N═N--, --CR¹ ═N--, --CR¹ ═N--N═CR¹ --, --CR¹ ═CR¹ --CO--,--O--CO--, --NR¹ --CO--, --CO--O--, --CO--NR¹ --, --CO--CR¹ ═CR¹ 13 ,--CR¹ ═CR¹ --O--CO--(CH₂)_(n') --, --N═CR¹ --, --(CH₂)_(n') --CO--O--CR¹═CR¹, --CR¹ ═CR¹ --O--CO--, --CO--O--CR¹ ═CR¹ --, --CO--O--N═CR¹ --,--CR¹ ═N--O--CO--, --CO--S--, --CR¹ ═CR¹ --CO--O--, --O--CO--CR¹ ═CR¹--, --CR¹ ═CR¹ --CO--O--(CH₂)_(n') --, --S--CO--, --(CH₂)_(n')--O--CO--CR¹ ═CR¹ --, --CHR¹ --CHR¹ --CO--O--, --O--CO--CHR¹ --CHR¹ --,--C.tbd.C--C.tbd.C--, --CR¹ ═CR¹ --CR¹ ═CR¹ --, --CO--NR¹ --NR¹ --CO--,##STR18## and the like; wherein R¹, A¹, v, n and n' are as hereinbeforedefined. As is well known in the prior art, all or a part of thearomatic rings can be replaced with other promesogenic structures, suchas, for example, the trans-cyclohexane ring or a cholesterol groupAdditionally, it is has been demonstrated in the prior art thatefficacious rodlike mesogen containing polymerizable ethylenicallyunsaturated monomers can be prepared with omission of the flexiblespacer between the polymerizable ethylenically unsaturated group and therodlike mesogenic group(s).

Generally, the ethylenically unsaturated monomers containing --CH═CH₂,acrylate, allyl, methallyl, propenyl, isopropenyl or methacrylate as thepolymerizable vinyl group and a linear divalent hydrocarbon groupconnecting the vinyl group and the rodlike mesogenic group throughheteroatom containing functional groups between the hydrocarbon spacerand the mesogenic group are most preferred. Thus, a rodlike mesogenicgroup ether linked to a --CH₂ --CH₂ -- which is in turn linked toprovide a methacrylate ester, that is, ##STR19## or a rodlike mesogenicgroup linked to a vinyl group, that is, ##STR20## are examples of thosespecies preferred as the ethylenically unsaturated monomer containingone or more rodlike mesogenic moieties.

Particularly suitable ethylenically unsaturated monomers containing arodlike mesogenic moiety include, for example, ##STR21## any combinationthereof and the like.

Suitable polymerizable ethylenically unsaturated monomers which do notcontain rodlike mesogenic structures can be selected from the many knownclasses of polymerizable vinyl monomers. Suitable such monomers include,for example, the vinyl aromatic compounds represented by the followingFormula XXXIII ##STR22## wherein each R¹ is as hereinbefore defined. Y²is independently hydrogen, a hydrocarbyl or hydrocarbyloxy group havingfrom 1 to about 5 carbon atoms, a vinyl group, an allyl group, amethallyl group, a propenyl group, a isopropenyl group, a nitro group, anitrile group, a halogen, such as chlorine or bromine or fluorine, or a--CO--R¹ group; each Y³ is independently hydrogen, a hydrocarbyl orhydrocarbyloxy group having from 1 to about 5 carbon atoms, or ahalogen, such as chlorine or bromine or fluorine and X is ##STR23## orthe acrylate or methacrylate compounds represented by the followingFormula XXXIV ##STR24## wherein R⁴ is a hydrocarbyl group having from 2to about 25 carbon atoms and may be branched, cyclic, polycyclic,saturated or unsaturated and R⁵ is hydrogen or a methyl group.

Typical polymerizable unsaturated monomers represented by Formula XXXIIIinclude, for example, styrene, alpha-methylstyrene, o-, m-,p-chlorostyrene; o-, m-, p-bromostyrene; o-, m-, p-tert-butylstyrene;o-, m-, p-methylstyrene, o-, m-, p-methoxystyrene; divinylbenzenes,trivinylbenzenes, o-, m-, p-isopropenylstyrene; o-, m-, p-allylstyrene;o-, m-, p-methallylstyrene; allylbenzene, methallylbenzene,diallylbenzenes and the like.

Typical acrylate (methacrylate) esters represented by Formula XXXIVinclude, for example, ethyl acrylate, n-butyl acrylate, n-butylmethacrylate, sec-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexylmethacrylate, n-dodecyl acrylate, cyclohexyl acrylate, methylcyclohexylacrylate, norbornyl acrylate, dicyclopentadiene acrylate,methyldicyclopentadiene acrylate and the like.

Other suitable monomers include the acidic monomers, such as acrylic andmethacrylic acid; the amide monomers, such as acrylamide andN-methylacrylamide; the allyl monomers, such as diallylphthalate,triallylisocyanurate, diallylmaleate and dimethallylfumarate; the vinylhalides, such as vinyl chloride and vinyl bromide; the vinyl esters,such as vinyl acetate; the vinyl di and polycyclic aromatics, such asvinyl naphthalene; the vinyl nitriles, such as acrylonitrile; and thehydroxyalkyl acrylates and methacrylates, such as 2-hydroxyethylacrylate.

COMPOUNDS CONTAINING BOTH A CYANATE OR CYANAMIDE GROUP AND APOLYMERIZABLE ETHYLENICALLY UNSATURATED GROUP FOR USE IN THE CURABLE ANDCURED COMPOSITIONS

Suitable compounds which contain both a cyanate or cyanamide group and apolymerizable ethylenically unsaturated group in the same molecule thatcan be used to prepare the polymerizable mixtures of the presentinvention include, for example, those represented by the followingFormula XXXV ##STR25## wherein each Y and R¹ are as hereinbeforedefined. Y⁴ is independently hydrogen, a hydrocarbyl or hydrocarbyloxygroup having from 1 to about 12 carbon atoms, a nitro group, a nitrilegroup, a halogen, such as chlorine or bromine or fluorine, or a --CO--R¹group; or a compound represented by the following Formula XXXVI##STR26## wherein each Y, Y⁴ and R¹ are as hereinbefore defined.

Suitable compounds which contain a cyanate or cyanamide group and apolymerizable ethylenically unsaturated group in the same moleculerepresented by Formulas XXXV and XXXVI include, for example, o-, m-,p-isopropenylphenyl cyanate; o-, m-, p-vinylphenyl cyanate;methyl-p-isopropenylphenyl cyanates; 3-chloro-4-isopropenylphenylcyanate; o-, m-, p-propenylphenyl cyanate; o-, m-, p-allylphenylcyanate; o-, m-, p-methallylphenyl cyanate and the like. Some of thealkenylphenol precursors to the alkenylphenyl cyanates represented byFormula XXXV, notably the vinylphenols, have a tendency to dimerize oroligomerize thus leading to poly(alkenylphenyl)cyanates. It is mostpreferred that the alkenylphenyl cyanate be substantially free ofdimeric and/or oligomeric components, although it is operable to use analkenylphenyl cyanate containing substantial (up to 90 percent byweight) dimeric and/or oligomeric components. A specific preparation ofp-isopropenylphenyl cyanate is taught in Example 1 of U.S. Pat. No.4,559,399 which is incorporated herein by reference.

COMPOUNDS CONTAINING BOTH A 1,2-EPOXIDE GROUP AND A POLYMERIZABLEETHYLENICALLY UNSATURATED GROUP FOR USE IN THE CURABLE AND CUREDCOMPOSITIONS

Suitable compounds which contain both a 1,2-epoxide group and apolymerizable ethylenically unsaturated group in the same molecule thatcan be used to prepare the polymerizable mixtures of the presentinvention include, for example, those represented by the followingFormulas XXXVII or XXXVIII ##STR27## wherein each Y⁴ and R¹ are ashereinbefore defined.

Suitable compounds which contain a 1,2-epoxide group and a polymerizableethylenically unsaturated group in the same molecule represented byFormulas XXXVII and XXXVIII include, for example, o-, m-,p-isopropenylphenyl glycidyl ether; o-, m-, p-vinylphenyl glycidylether; methyl-p-isopropenylphenyl glycidyl ethers;3-chloro-4-isopropenylphenyl glycidyl ether; o-, m-, p-propenylphenylglycidyl ether; o-, m-, p-allylphenyl glycidyl ether; o-, m-,p-methallyphenyl glycidyl ether and the like. Some of the alkenylphenolprecursors to the alkenylphenyl glycidyl ethers represented by FormulaXXXVII, notably the vinylphenols, have a tendency to dimerize oroligomerize thus leading to poly(alkenylphenyl)glycidyl ethers. It ismost preferred that the alkenylphenyl glycidyl ether be substantiallyfree of dimeric and/or oligomeric components, although it is operable touse an alkenylphenyl glycidyl ether containing substantial (up to 90percent by weight) dimeric and/or oligomeric components. The compoundswhich contain a 1,2-epoxide group and a polymerizable ethylenicallyunsaturated group in the same molecule are prepared using thecorresponding phenol containing a polymerizable ethylenicallyunsaturated group and the hereinbefore described chemistry used in thepreparation of epoxy resins.

COMPOUNDS CONTAINING BOTH A MALEIMIDE GROUP AND A CYANATE GROUP SUITABLEFOR USE IN THE CURABLE AND CURED COMPOSITIONS

Suitable compounds which contain both a maleimide group and a cyanategroup in the same molecule that can be used to prepare the polymerizablemixtures of the present invention include, for example, thoserepresented by the following Formulas XXXIX, XXXX or XXXXI ##STR28##wherein each Y⁴, R¹, A, A" and n are as hereinbefore defined.

Suitable compounds which contain a maleimide group and a cyanate groupin the same molecule represented by Formulas XXXIX, XXXX and XXXXIinclude, for example,4-(1-(3-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenyl)-1-methylethyl)phenylcyanate; 4-(1-(4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenyl)-1-methylethyl)phenyl cyanate;4-(1-(4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenyl)ethyl)phenylcyanate; 4-(4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenoxy)phenylcyanate; 4-((4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenyl)thio)phenylcyanate; 4-(4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)benzoyl)phenylcyanate;4-((4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenyl)sulfonyl)phenylcyanate;4-(1-(4-(2,5-dihydro-3-methyl-2,5-dioxo-1H-pyrrol-1-yl)phenyl)-1-methylethyl)phenylcyanate;2,6-dibromo-4-(1-(3,5-dibromo-4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenyl)-1-methylethyl)phenylcyanate;4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenyl cyanate;3-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phenyl cyanate and the like.Preparation of compounds which contain a maleimide group and a cyanategroup in the same molecule is taught in U.S. Pat. No. 4,683,276 which isincorporated herein by reference.

COMPOUNDS CONTAINING ONE CYANATE OR CYANAMIDE GROUP PER MOLECULE AND ONEOR MORE RODLIKE MESOGENIC MOIETIES WHICH CAN BE EMPLOYED IN THE CURABLEAND CURED COMPOSITIONS

Suitable compounds which contain one or more rodlike mesogenicstructure(s) and an average of one cyanate or cyanamide group permolecule that can be used to prepare the polymerizable mixtures of thepresent invention include, for example, those represented by thefollowing Formulas XXXXII, XXXXIII, XXXXIV, or XXXXV ##STR29## whereinat least 80 percent of the --A-- linkages. The direct bond in FormulaXXXXIV and the Y groups are in the para position with respect to eachother and each A, A', A", R, Y, n and p are as hereinbefore defined andq has a value from zero to about 6, preferably zero to about 3.

Suitable compounds which contain one or more rodlike mesogenicstructure(s) and an average of one cyanate or cyanamide group permolecule represented by Formulas as XXXXII, XXXXIII, XXXX IV and XXXXVinclude, for example, the cyanates of 4-hydroxystilbene,4-hydroxy-4'-methoxystilbene, 4-hydroxy-4'-chlorostilbene,4-hydroxy-4'-nitrostilbene, 4- hydroxy-4'-cyanostilbene,4-hydroxy-alpha-methylstilbene, 4-hydroxychalcone,1-(4-hydroxyphenyl)-2-phenylacetylene,1-(4-hydroxyphenyl)-2-phenylazomethine, 4-hydroxyphenylazobenzene,4-hydroxyphenylazoxybenzene, 4-(4-hydroxyphenoxy)diphenyl,4-hydroxydiphenyl, 4-hydroxy-alpha-cyanostilbene,4-hydroxy-alpha-ethylstilbene, 4-hydroxybenzanilide,4-hydroxy-4'-methoxybenzanilide,4-hydroxy-3,3',5,5'-tetramethyl-alpha-methylstilbene,N-methyl-4-hydroxybenzamide, N-phenyl-4-hydroxybenzamide,4-hydroxy-3,3',5,5'-tetrabromo-alpha-methylstilbene,4-hydroxyphenylbenzoate, phenyl-4-hydroxybenzoate, the cyanamides of4-aminostilbene, 4-amino-alpha-methylstilbene, 4-aminobenzanilide, andthe like. The compounds which contain one or more rodlike mesogenicstructure(s) and an average of one cyanate or cyanamide group permolecule are prepared using the corresponding monophenol (monoamine)containing one or more rodlike mesogenic structure(s) and thehereinbefore described chemistry used in the preparation of polycyanates(polycyanamides).

METHOD FOR FORMING THE MIXTURES OF THE PRESENT INVENTION

The mixtures of the present invention can be prepared by directlycombining one or more of the desired component(s) with one or morepolycyanates or polycyanamides containing one or more rodlike mesogenicstructures or by addition of one or more of the desired components tothe polycyanates or polycyanamides containing one or more rodlikemesogenic structures in increments or stages. When a single component isto be added to the polycyanates or polycyanamides containing one or morerodlike mesogenic structures, said component may be prepolymerized(B-staged) or fully homopolymerized, prior to the addition.Additionally, certain of said single components may be homopolymerized(interpolymerized) while dispersed in or mixed in with one or morepolycyanates or polycyanamides containing one or more rodlike mesogenicstructures. When two or more components are to be added to thepolycyanates or polycyanamides containing one or more rodlike mesogenicstructures, said components may be partially or totally copolymerized orreacted together, prior to the addition. Additionally, when two or morecomponents are to be added to the polycyanates or polycyanamidescontaining one or more rodlike mesogenic structures, one component maybe prepolymerized or fully homopolymerized in the presence of the othercomponents, prior to the addition. It is understood that one or morecatalysts or accelerators may be included where desired to facilitatethe aforementioned copolymeriza-tion, interpolymerization,prepolymerization, homopolymerization or reaction of one or morespecific components.

The mixtures of the thermosettable polycyanate or polycyanamidecontaining one or more rodlike mesogenic moieties (component A) and thecomponents B-1 to B-12 can contain any amounts of components A and B.Suitably, the components are employed in amounts such that the mixturecontains from about 1 to about 99, preferably from about 25 to about 95,more preferably from about 50 to about 90 percent by weight of componentA based on the combined weight of components A and B; and from about 99to about 1, preferably from about 75 to about 5, more preferably fromabout 50 to about 10 percent by weight based on the combined weight ofcomponents A and B.

POLYMERIZATION OF THE POLYMERIZABLE MIXTURES

The mixtures of the present invention may be polymerized by heating fromabout 50° C. to about 400° C., preferably by heating from 100° C. to250° C., optionally in the presence of one or more suitable catalysts.In addition to the catalysts previously delineated for thepolymerization of polycyanates or polycyanamides, whenever one or morepolymaleimides, compounds containing one or more polymerizableethylenically unsaturated group(s), compounds which simultaneouslycontain both a cyanate or cyanamide group and a polymerizableethylenically unsaturated group, compounds which simultaneously containboth a 1,2-epoxide group and a polymerizable ethylenically unsaturatedgroup or compounds which simultaneously contain both a maleimide groupand a cyanate group it is often desireable to utilize one or more freeradical forming catalysts for the purpose of polymerizing all or a partof said unsaturated groups. Said free radical forming catalysts includethe organic peroxides and hydroperoxides as well as the azo and diazocompounds. Preferred free radical forming catalysts includebenzoylperoxide, t-butylhydroperoxide, t-butylperoxybenzoate,azobisisobutyronitrile, dicumylperoxide, di-tert-butylperoxide andcumene hydroperoxide. The quantity of catalyst used, if any, depends onthe structure of the particular catalyst, the structure of thecomponents used in the polymerizable mixture, the cure structuredesired, the cure time, the cure temperature, and the like. Generally,catalyst concentrations of from about 0.001 to about 2 percent by weightare preferred. B-staging or prepolymerization of the mixtures of thepresent invention can be accomplished by using lower temperatures and/orshorter curing times. Curing of the thus formed B-staged(prepolymerized) mixture can then be accomplished at a later time orimmediately following B-staging (prepolymerization) by increasing thetemperature and/or curing time.

The polymerized mixtures possess a variety of curing structures whichdepend, in part, upon the amounts and types of individual componentsused to prepare said mixture, the sequence of component addition andprocedure used to prepare said mixture, the amounts and types ofcatalysts, if any, employed, the reaction times and temperatures, andthe like.

Mixtures of (A) one or more polycyanates containing one or more rodlikemesogenic structures and no other moieties reactive with the cyanategroup with (B-1) one or more polycyanates which do not contain rodlikemesogenic structures and/or prepolymers of either of the aforementionedtypes of polycyanates cure via cyclotrimerization of the cyanatemoieties to provide the polytriazine thermoset. As a preferredembodiment of the present invention, addition of about 10 percent ormore of a polycyanate containing one or more rodlike mesogenicstructures to a polycyanate which does not contain rodlike mesogenicstructures followed by polymerizing or curing provides a polytriazinewith improved mechanical properties over those of the polytriazineobtained from curing or polymerizing of only the polycyanate which doesnot contain rodlike mesogenic structures.

Mixtures of (A) one or more polycyanates containing one or more rodlikemesogenic structures and no other moieties reactive with the cyanategroup with (B-2) one or more epoxy resins using a 1 to 1 mole ratio ofcyanate groups to epoxide groups polymerize to produce a complexstructure. Increasing the mole ratio of cyanate to epoxide groups can bedone to increase the relative amount of triazine groups in the curedproduct. A preferred embodiment of the present invention is thepolymerization product of a polycyanate containing one or more rodlikemesogenic structures with an epoxy resin containing one or more rodlikemesogenic structures. The aforementioned polymerized product providesimproved properties, notably increased glass transition temperature,relative to the polymerization product of a polycyanate containing oneor more rodlike mesogenic structures with an epoxy resin which does notcontain rodlike mesogenic structures.

Mixtures of (A) one or more polycyanates containing one or more rodlikemesogenic structures and no other moieties reactive with the cyanategroup with (B-3) one or more polymaleimides can polymerize to produce acomplex variety of structures including the triazine group resultingfrom cyclotrimerization of cyanate moieties ##STR30## the maleimidegroup homopolymerization structure, ##STR31## and cyanate group andmaleimide group copolymerization structures such as, for example,##STR32## Changes in the mole ratio of cyanate groups and maleimidegroups can be made to influence the composition of the cured product.Increasing the mole ratio of cyanate groups to maleimide groups to above1 to 1 can be done to increase the relative amount of triazine groups inthe polymerized product. A decrease in the mole ratio of cyanate groupsto maleimide groups to below 1 to 1 favors an increase in the amount ofmaleimide group homopolymerization structure in the cured product. Apreferred embodiment of the present invention is the polymerizationproduct of a polycyanate containing one or more rodlike mesogenicstructures with a polymaleimide containing one or more rodlike mesogenicstructures. The aforementioned polymerized product provides improvedmechanical properties relative to the polymerization product of apolycyanate containing one or more rodlike mesogenic structures with apolymaleimide which does not contain rodlike mesogenic structures.Methods for the copolymerization of polycyanates which do not containrodlike mesogenic structures with polymaleimides are taught by U.S. Pat.Nos. 4,469,859; 4,404,330; 4,396,745; 4,383,903; 4,373,086; 4,371,689;4,369,304; 4,287,014 and 4,110,364 which are incorporated herein byreference.

Mixtures of (A) one or more polycyanates containing one or more rodlikemesogenic structures and no other moieties reactive with the cyanategroup with (B-4) one or more polyamines using a 1 to 1 mole ratio ofcyanate groups to amine groups polymerize to produce poly(iminocarbamicacid esters). Increasing the mole ratio of cyanate to amine groups canbe done to induce formation of triazine groups in the polymerized orcured product. Methods for the reaction of polyamino compounds withpolycyanate compounds to produce poly(iminocarbamic acid esters) aretaught by U.S. Pat. No. 3,502,617 which is incorporated herein byreference.

Mixtures of (A) one or more polycyanates containing one or more rodlikemesogenic structures and no other moieties reactive with the cyanategroup with (B-5) one or more polyphenols using a 1 to 1 mole ratio ofcyanate groups to phenolic hydroxyl groups polymerize to producepoly(iminocarbonic acid esters). Increasing the mole ratio of cyanate tophenolic hydroxyl groups can be done to induce formation of triazinegroups in the polymerized or cured product. Methods for the reaction ofpolyphenol compounds with polycyanate compounds to producepoly(iminocarbonic acid esters) are taught by U.S. Pat. No. 3,491,060which is incorporated herein by reference.

Mixtures of (A) one or more polycyanates containing one or more rodlikemesogenic or structure(s) and no other moieties reactive with thecyanate group with (B-6) one or more polymerizable ethylenicallyunsaturated compounds can polymerize to produce a complex variety ofstructures including the triazine group resulting fromcyclotrimerization of cyanate moieties, structure from thepolymerization of the polymerizable ethylenically unsaturatedcompound(s) and cyanate group and polymerizable ethylenicallyunsaturated group copolymerization structures. A specific example of astructure arising from the copolymerization of cyanate groups with avinyl aromatic group (styrene) is as follows: ##STR33## Changes in themole ratio of cyanate groups and polymerizable ethylenically unsaturatedgroups can be made to influence the composition of the polymerizedproduct. Increasing the mole ratio of cyanate groups to polymerizableethylenically unsaturated groups to above 1 to 1 can be done to increasethe relative amount of triazine groups in the polymerized product. Adecrease in the mole ratio of cyanate groups to polymerizableethylenically unsaturated groups to below 1 to 1 favors an increase inthe amount of polymerizable ethylenically unsaturated grouphomopolymerization structure in the polymerized product. A preferredembodiment of the present invention is the polymerization product of apolycyanate containing one or more rodlike mesogenic structures with apolymerizable ethylenically unsaturated compound containing one or morerodlike mesogenic structures. The aforementioned polymerized productprovides improved mechanical properties relative to the polymerizationproduct of a polycyanate containing one or more rodlike mesogenicstructures with a polymerizable ethylenically unsaturated compound whichdoes not contain rodlike mesogenic structures. Methods for thecopolymerization of a specific class of polycyanates which do notcontain rodlike mesogenic structures with vinyl aromatic monomers aretaught by U.S. Pat. No. 4,746,727 which is incorporated herein byreference.

Mixtures of (A) one or more polycyanates containing one or more rodlikemesogenic structures and no other moieties reactive with the cyanategroup with (B-7) one or more compounds which simultaneously contain botha cyanate group and a polymerizable ethylenically unsaturated group or(B-8) one or more compounds which simultaneously contain both a1,2-epoxide group and a polymerizable ethylenically unsaturated group or(B-9) one or more compounds which simultaneously contain both amaleimide group and a cyanate group can polymerize to produce a complexvariety of structures, including those previously mentioned for thevarious respective functional groups. As a specific example, a preferredmixture of the present invention consists of the polymerization productof (B-7) one or more compounds which simultaneously contain both acyanate group and a polymerizable ethylenically unsaturated group with(B-6) one or more compounds containing one or more ethylenicallyunsaturated groups. This copolymer is either prepared in situ by freeradical initiated polymerization of the (B-6) and (B-7) components in amolten or solvent solution of (A) one or more polycyanates containingone or more rodlike mesogenic structures or it may be preparedseparately then added to component (A). The resultant mixture is apolymer modified polycyanate which can be homopolymerized to provide thecorresponding polymer modified polytriazine. In a further preferredembodiment of the present invention, if component (B-6) consists of oneor more compounds containing ethylenically unsaturated groups and one ormore rodlike mesogenic structures, liquid crystal polymer modifiedpolycyanates and polytriazines thereof can be produced via theaforementioned technique. Preparation of polymer modified cyanates whichdo not contain rodlike mesogenic structures is taught by U.S. Pat. No.4,559,399 which is incorporated herein by reference.

Mixtures of (A) one or more polycyanates containing one or more rodlikemesogenic structures with (B-10) one or more compounds which contain oneor more rodlike mesogenic structures per molecule and only one cyanate(cyanamide) group per molecule can be cured via cyclotrimerization ofthe cyanate moieties to provide the polytriazine thermoset, providingthat no other moieties reactive with cyanate groups are present in (A)or (B-10). Increasing the amount of the aforementioned cyanate compoundcontaining an average of one cyanate group per molecule with respect tothe amount of polycyanate can be used as a convenient method forlowering the crosslink density of the polytriazine product thereof.

ORIENTATION OF THE POLYMERIZED PRODUCT CONTAINING RODLIKE MESOGENICSTRUCTURES

During processing and/or curing of the polycyanates or polycyanamidescontaining one or more rodlike mesogenic structures or the mixturescontaining said polycyanates or polycyanamides, electric or magneticfields or shear stresses can be applied for the purpose of orienting therodlike mesogenic moieties contained or developed therein. As specificexamples of these methods, Finkelmann, et. al., Macromol. Chem., 180,803-806 (March, 1979), incorporated herein by reference, inducedorientation in an electric field, of thermotropic methacrylatecopolymers containing mesogenic side chain groups decoupled from themain chain via flexible spacers. Orientation in a magnetic field ofmesogenic side chain groups decoupled from the main chain via flexiblespacers has been demonstrated by Roth and Kruecke, Macromol. Chem., 187,2655-2662 (November, 1986) which is incorporated herein by reference.Magnetic field induced orientation of mesogenic main chain containingpolymers has been demonstrated by Moore, et. al., ACS Polymeric MaterialSciences and Engineering, 52, 84-86 (April-May, 1985) which isincorporated herein by reference. Magnetic and electric field inducedorientation of low molecular weight mesogenic compounds is discussed byW. Krigbaum in Polymer Liquid Crystals , pages 275-309 (1982), publishedby Academic Press, Inc., and is incorporated herein by reference. Theuse of shear to induce orientation is also discussed therein. When thecuring is to be performed in an electric or magnetic field, it isfrequently of value to conduct simple preliminary experiments that allowfor balancing of cure kinetics versus induction of orientation under theparticular experimental conditions being employed (i.e. catalyst(s)level being used, temperature used, inherent dielectric (diamagnetic)susceptibility of the specific rodlike mesogenic structure(s) used,etc.). This is done recognizing the relatively greater ease of inducingorientation in low molecular weight materials versus polymeric materialscontaining rodlike mesogenic moieties.

In addition to orientation by electric or magnetic fields, thepolycyanates or polycyanamides containing one or more rodlike mesogenicstructures or mixtures containing said polycyanates or polycyanamidescan be oriented by shear forces which are induced by flow through dies,orifices and mold gates. A general discussion of orientation ofthermotropic liquid crystalline polymers by this method is given by S.K. Garg and S. Kenig in High Modulus Polymers, pages 71-103 (1988)published by Marcel Dekker, Inc. which is incorporated herein byreference. For the rodlike mesogen-containing polycyanates or mixturescontaining said polycyanates, this shear orientation can conveniently beproduced by or during processing methods such as injection molding,extrusion, pultrusion, filament winding, filming and prepreging.

OTHER COMPONENTS WHICH CAN BE EMPLOYED

The polycyanates or polycyanamides containing one or more rodlikemesogenic structures or mixtures containing said polycyanates orpolycyanamides can be blended with other materials such as solvents ordiluents, fillers including those comprising a liquid crystallinepolymer, pigments, dyes, flow modifiers, thickeners, reinforcing agents,mold release agents, wetting agents, stabilizers, fire retardant agents,surfactants, low profile additives, shrinkage control agents, otherresinous products, combinations thereof and the like.

These additives are added in functionally equivalent amounts, e.g., thepigments and/or dyes are added in quantities which will provide thecomposition with the desired color; however, they are suitably employedin amounts of from about zero to about 20, more suitably from about 0.5to about 5, most suitably from about 0.5 to about 3 percent by weightbased on the total weight of the composition.

Solvents or diluents which can be employed herein include, for example,hydrocarbons, ketones, aliphatic ethers, cyclic ethers, esters,chlorinated hydrocarbons, combinations thereof and the like.Particularly suitable solvents or diluents include, for example,toluene, xylenes, methylethyl ketone, methylisobutyl ketone, methylamylketone, chloroform, acetone, perchloroethylene, methylene chloride,tetrahydrofuran, 1,4-dioxane, ethyl acetate, butyl acetate, combinationsthereof and the like.

The modifiers such as thickeners, flow modifiers, shrinkage controlagents, low profile additives and the like can be suitably employed inamounts from about 0.05 to about 15, more suitably from about 0.1 toabout 10, most suitably from about 0.1 to about 5 percent by weightbased on the total weight of the composition.

Reinforcing materials which can be employed herein include natural andsynthetic fibers in the form of woven fabric, mats, monofilament,multifilament, unidirectional fibers, rovings, random fibers orfilaments, inorganic fillers or whiskers, hollow spheres, and the like.Suitable reinforceing materials include glass, ceramics, nylon, rayon,cotton, aramid, graphite, polyalkylene terephthlates, polyethylene,polypropylene, polyesters, carbon, boron, asbestos, combinations andhybrids thereof and the like.

Suitable fillers which can be employed herein include, for example,inorganic oxides, ceramic microspheres, plastic microspheres, glassmicrospheres, inorganic whiskers, calcium carbonate, graphite powder,sand, metal powders, combinations thereof and the like. The fillers canbe employed in amounts from about 0.1 to about 95, more suitably fromabout 5 to about 80, most suitably from about 10 to about 50 percent byweight of the total composition.

USES FOR THE COMPOSITIONS

The compositions of the present invention can be employed in thepreparation of laminates, prepregs, composites, coatings, castings,pultruded products, filament wound products, films, molding and pottingformulations, injection molded products, and the like.

The following examples are illustrative of the invention but are not tobe construed as to limiting the scope thereof in any manner.

EXAMPLE 1

A. Synthesis of 4,4'-Dihydroxy-alpha-methylstilbene

Phenol (376.44 grams, 4.0 moles), chloroacetone (205.62 grams, 2.0 molesas chloroacetone) and methylene chloride (300 grams) are added to areactor and cooled to -10° C. with stirring. The chloroacetone used is atechnical grade containing 90% chloroacetone, 2.5% acetone, 6.5%1,1-dichloroacetone and 1.0% 1,3-dichloroacetone. Concentrated sulfuricacid (196.16 grams, 2.0 mole) is added dropwise to the stirred solutionover a one hour period and so as so maintain the reaction temperature at-10° C. After two hours of post reaction at the -10° C. temperature, theviscous orange oil solution is mixed with 500 milliliters of iceddeionized water. The oil solution is separated then washed with a second500 milliliter portion of iced deionized water. After separation, therecovered oil solution is added to a 2 liter beaker along with 250milliliters of ethanol and stirred to provide a solution. Deionizedwater (250 milliliters) is added to the stirred solution and heatingcommenced. As the temperature of the mixture increased, the stirredmixture began to clear. Each time clearing is observed, sufficientdeionized water is added to induce cloudiness, followed by continuationof the mixing and heating. Once the temperature reached 70° C., amassive precipitation of white crystalline plates occurred and isfollowed by immediate coalesence of the precipitated product to an oil.The oil layer is recovered by decantation of the water layer and 250milliliters of ethanol is added. Deionized water is again added to thestirred solution as heating commenced, in an amount sufficient to inducecloudiness each time clearing is observed. Once the temperature reached90° C., a massive precipitation of white crystalline plates againoccurred. At this time, stirring is stopped and the crystalline slurry,as well as the decanted water layer are both chilled to 5° C. and heldtherein for 12 hours. The crystalline product is recovered by filtrationthen combined with 250 milliliters of deionized water then stirred withheating to 90° C. After cooling to 5° C., the crystalline product isrecovered by filtration then dried in a vacuum oven at 100° C. and 5 mmHg to a constant weight of 243.3 grams. Proton magnetic resonancespectroscopy and infrared spectrophotometric analysis confirmed theproduct structure.

B. Preparation of Dicyanate of 4,4'-Dihydroxy-alpha-methylstilbene

4,4'-Dihydroxy-alpha-methylstilbene (226.26 grams, 2.0 hydroxylequivalents) prepared using the method of A above, cyanogen bromide(222.45 grams, 2.10 moles) and acetone (1200 milliliters) are added to areactor and maintained under a nitrogen atmosphere with stirring. Thestirred solution is cooled to -5° C., then triethylamine (203.39 grams,2.01 moles) is added to the reactor over a 34 minute period and so as tomaintain the reaction temperature at -5° to -3° C. After completion ofthe triethylamine addition, the reactor is maintained at -5° to -3° C.for an additional 45 minutes followed by addition of the reactorcontents to 1 gallon of deionized water. After 5 minutes, the water andproduct mixture is multiply extracted with three 400 milliliter volumesof methylene chloride. The combined methylene chloride extract is washedwith 250 milliliters of 0.05 percent by weight aqueous hydrochloric acidfollowed by washing with two 500 milliliter portions of deionized water,then drying over anhydrous sodium sulfate. The dry methylene chlorideextract is filtered and solvent removed by rotary evaporation under avacuum for 60 minutes at 100° C. The dicyanate of4,4'-dihydroxy-alpha-methylstilbene (272.5 grams) is recovered in 98.64percent yield as a mass of light tan colored crystalline needles.Infrared spectrophotometric analysis of a film sample of the productconfirmed the product structure (disappearance of phenolic hydroxylabsorbance, appearance of cyanate absorbance (2236 and 2270 cm⁻¹,sharp)).

C. Characterization of the Dicyanate of4,4'-Dihydroxy-alpha-methylstilbene for Liquid Crystallinity

A portion (10.28 milligrams) of the dicyanate4,4'-dihydroxy-alpha-methylstilbene from B above is analyzed bydifferential scanning calorimetry using a heating rate of 10° C. perminute and the indicated temperature ranges. The results are given inTable I.

                  TABLE I                                                         ______________________________________                                                   OBSERVED                                                                      TRANSITION                                                                    TEMPERATURES                                                                  (°C.)  EN-                                                  CYCLE      MIDPOINT/     THALPY    COM-                                       DESIGNATION                                                                              RANGE         (J/g)     MENTS                                      ______________________________________                                        First heating                                                                            81/52-90      --        Single                                     (30 to 200° C.)             peak                                       First cooling                                                                            42/56-28      --        Single                                     (200 to 0° C.)              peak                                       Second heating                                                                           70.8/50-74    26.52     Two                                        (0 to 200° C.)                                                                    79.4/74-88    17.57     resolved                                                                      peaks                                      Second cooling                                                                           42/56-26      53.58     Single                                     (200 to -50° C.)            peak                                       Third heating                                                                            unchanged from                                                                              unchanged unchanged                                  (-50 to 150° C.)                                                                  second heating                                                                              from      from                                                                second    second                                                              heating   heating                                    ______________________________________                                    

Analysis of the dicyanate via cross polarized light microscopy iscompleted using a microscope equipped with a programmable hot stageusing a heating rate of 10° C. per minute and 35× magnification. Theresults are given in Table II.

                  TABLE II                                                        ______________________________________                                                 OBSERVED                                                             CYCLE    TRANSITION                                                           DESIG-   TEMPERATURES                                                         NATION   (°C.)  COMMENTS                                               ______________________________________                                        First    25            Immobile crystals.                                     Heating  67            First fluidity noted.                                           76            Crystals moving in fluid,                                                     crystals are restructuring.                                     82            Isotropization complete.                               First    61            First crystallization noted.                           Cooling  58            Immobile crystalline mass.                             Second   25            Immobile crystals.                                     Heating  67            First fluidity noted.                                           76            Crystals moving in fluid,                                                     crystals are restructuring.                                     82            Isotropization complete.                               ______________________________________                                    

D. Preparation of a Cured Polytriazine Casting from the Dicyanate of4,4'-Dihydroxy-alpha-methylstilbene

A 250.0 gram portion of the dicyanate of4,4'-dihydroxy-alpha-methylstilbene from B above is heated to 100° C. toform a solution, cooled to 50° C., then 0.25 gram of cobalt naphthenate(6.0 percent active) is added and mixed in. This solution is reheated to100° C., filtered, poured into a 1/8 inch mold, then placed in an ovenand maintained at 125° C. for 2 hours, 177° C. for 4 hours, 200° C. for4 hours then 250° C. for 2 hours. The transparent, light amber coloredcasting is demolded and used to prepare test pieces for tensile andflexural strength and modulus, tensile elongation and average Barcolhardness (934-1 scale). Mechanical properties of the tensile andflexural test pieces are determined using an Instron machine withstandard test methods (ASTM D 638 and D 790). The results are reportedin Table III.

COMPARATIVE EXPERIMENT A

A. Preparation of Bisphenol A Dicyanate

4,4'-Isopropylidene diphenol (456.60 grams, 4.0 hydroxyl equivalents),cyanogen bromide (444.91 grams, 4.20 moles) and acetone (1100milliliters) are added to a reactor and maintained under a nitrogenatmosphere with stirring. The stirred solution is cooled to -5° C., thentriethylamine (406.82 grams, 4.02 moles) is added over a 60 minuteperiod and so as to maintain the reaction temperature at -5° to -3° C.After completion of the triethylamine addition, the reactor ismaintained at -5° to -3° C. for an additional 25 minutes followed byaddition of the reactor contents to 1.5 gallons of deionized water.After 5 minutes, the water and product mixture is multiply extractedwith three 500 milliliter volumes of methylene chloride. The combinedmethylene chloride extract is washed with 500 milliliters of 0.05percent by weight aqueous hydrochloric acid followed by washing with 500milliliters of deionized water, then drying over anhydrous sodiumsulfate. The dry methylene chloride extract is filtered and solventremoved by rotary evaporation under vacuum for 60 minutes at 100° C. Thebisphenol A dicyanate (545.8 grams) is recovered in 98.1 percent yieldas a tan colored crystalline solid. Infrared spectrophotometric analysisof a film sample of the product confirmed the product structure(disappearance of phenolic hydroxyl, absorbance, appearance of cyanateabsorbance).

B. Preparation of a Cured Polytriazine Casting from Bisphenol ADicyanate

A 200.0 gram portion of bisphenol A dicyanate prepared using the methodof A above is heated to 100° C. to form a solution, cooled to 50° C.,then 0.20 gram of cobalt naphthenate (6.0 percent active) is added andmixed in. This solution is reheated to 100° C. filtered, poured into a1/8 inch mold, then placed in an oven and maintained at 125° C. for 2hours, 177° C. for 4 hours, 200° C. for 4 hours, then 250° C. for 2hours. The transparent, light amber colored casting is demolded and usedto prepare test pieces which are tested using the method of Example 1-D.The results are reported in Table III.

                  TABLE III                                                       ______________________________________                                                                COMPARATIVE                                           MECHANICAL  EXAMPLE     EXPERIMENT                                            PROPERTY    1-D         A-B                                                   ______________________________________                                        Barcol Hardness                                                                           51          48                                                    Tensile Strength                                                                          15,010      13,080                                                (psi)                                                                         Tensile Modulus                                                                           549,301     510,336                                               (psi)                                                                         Elongation (%)                                                                            3.87        3.26                                                  Flexural Strength                                                                         24,442      19,176                                                (psi)                                                                         Flexural Modulus                                                                          568,556     555,138                                               (psi)                                                                         ______________________________________                                    

Examination of a portion of the polytriazine casting of Example 1-Dusing cross polarized light microscopy revealed birefringence. By way ofcontrast, no birefringence is observed in the casting of ComparativeExperiment A-B.

EXAMPLE 2

Differential Scanning Calorimetry

A portion (8.0 milligrams) of the dicyanate of4,4'-dihydroxy-alpha-methylstilbene catalyzed with cobalt naphthenatefrom Example 1-D above is analyzed by differential scanning calorimetry(DSC). A first heating from 25° to 325° C. is completed at a rate of 10°C. per minute under a stream of nitrogen flowing at 35 cubic centimetersper minute resulting in the exothermic curing of the dicyanate.Similarly, a second heating is completed, with the glass transitiontemperature for the cured polytriazine determined from the data of thisheating. The results are reported in Table IV.

COMPARATIVE EXPERIMENT B

The method of Example 2 is repeated using a portion (7.7 milligrams) ofbisphenol A dicyanate catalyzed with cobalt naphthenate from ComparativeExperiment A-B. The results are reported in Table IV.

                  TABLE IV                                                        ______________________________________                                                   GLASS TRANSITION                                                              TEMPERATURE                                                        SAMPLE       ONSET      MIDPOINT   END                                        DESIGNATION  (°C.)                                                                             (°C.)                                                                             (°C.)                               ______________________________________                                        Example 1-D  263.1      288.2      308.1                                      Comparative  235.9      251.1      256.9                                      Experiment A-B                                                                ______________________________________                                    

EXAMPLE 3

Sets of four flexural strength test pieces prepared from the castings ofExample 1-D and Comparative Experiment A-B are weighed, then immersed indeionized water contained in individual jars and maintained at 92° C.The test pieces are weighed at the indicated intervals and the percentweight gain calculated as follows: 100 ((exposed weight-initialweight)/initial weight). An average of the percent weight gain is thencalculated with the results reported in Table V.

                  TABLE V                                                         ______________________________________                                                     PERCENT WEIGHT GAIN                                              SAMPLE         (hours of exposure)                                            DESIGNATION    24     48        72   94                                       ______________________________________                                        Example 1-D    1.31   1.81      2.12 2.30                                     Comparative    1.93   2.37      2.57 2.69                                     Experiment A-B                                                                ______________________________________                                    

EXAMPLE 4

A. Synthesis of bis(4'-Hydroxyphenyl)-1,4-benzenediimine

p-Aminophenol (327.4 grams, 3.00 moles) and methanol (1300 milliliters)are added to a 2 liter round bottom flask with stirring.Terephthaldehyde (201.2 grams, 1.50 moles) is added to the reactorfollowed by heating to 50° C. After 3 hours at 50° C., the reactionmixture is vacuum filtered and the solids thus obtained are washed withmethanol (500 milliliters). The washed solids are added back to thereactor along with additional methanol (1300 milliliters) and thenheated with stirring to reflux. After refluxing for one hour, themixture is again vacuum filtered with the recovered solids again addedback to the reactor along with fresh methanol (950 milliliters). Afterrefluxing for one hour, the mixture is vacuum filtered and the solidsthus recovered are dried at 80° C. for four hours in a vacuum oven to aconstant weight. The product is recovered (423.4 grams) as a lightyellow colored powder in 89.2 percent yield. Differential scanningcalorimetry of a portion of the product revealed a sharp melting pointendotherm at 270° C. Infrared spectrophotometric analysis of a film of anujol mull of a portion of the product confirmed the structure phenolichydroxyl absorbance (3370 cm⁻¹, broad), --CH═N-- stretching absorbance(1618 cm⁻¹, sharp)).

B. Preparation of Dicyanate of bis(4'-Hydroxyphenyl)-1,4-benzenediimine

bis(4'-Hydroxyphenyl)-1,4-benzenediimine (137.85 grams, 0.8716 hydroxylequivalent) from A above, cyanogen bromide (96.94 grams, 0.915 mole) andacetone (1000 milliliters) are added to a reactor and maintained under anitrogen atmosphere with stirring. The stirred solution is cooled to -5°C., then triethylamine (89.08 grams, 0.8803 moles) is added to thereactor over a 33 minute period and so as to maintain the reactiontemperature at -5° to -3° C. After completion of the triethylamineaddition, the reactor is maintained at -5° C. to -3° C. for anadditional 45 minutes followed by addition of the reactor contents to 1gallon of deionized water. After 5 minutes, the water and productmixture is filtered through a fritted glass funnel and the resultantcake of yellow powder is washed by slurrying into 250 milliliters ofdeionized water. A second filtration recovered the yellow powder whichis washed by slurring into 250 milliliters of methylene chloride. Athird filtration recovered the yellow powder which is washed for a finaltime by slurring into 500 milliliters of deionized water followed byfiltration to recover the yellow powder product. The dicyanate ofbis(4'-hydroxyphenyl)-1,4-benzenediimine (155.1 grams) is recovered in97.16 percent yield as a light yellow colored powder after drying at100° C. in a vacuum oven to constant weight. Infrared spectrophotometricanalysis of a nujol mull of a portion of the product confirmed theproduct structure (disappearance of phenolic hydroxyl absorbance (3370cm⁻¹, broad), appearance of cyanate absorbance (2234 and 2272 cm⁻¹,sharp) retention of the --CH═N-- stretching absorbance (1620 cm⁻¹,sharp)).

C. Evaluation of the Curing Behavior of the Dicyanate ofbis(4'-Hydroxyphenyl)-1,4-benzenediimine Using Differential ScanningCalorimetry and Infrared Spectrophotometric Analysis

A portion (8.75 milligrams) of the dicyanate ofbis(4'-hydroxyphenyl)-1,4-benzenediimine (uncatalyzed) from B above isanalyzed by differential scanning calorimetry (DSC). Heating from 25° to330° C. is completed at a rate of 10° C. per minute under a stream ofnitrogen flowing at 35 cubic centimeters per minute resulting in theexothermic curing of the dicyanate. The results are reported in TableVI.

                  TABLE VI                                                        ______________________________________                                        DESCRIPTION OF                                                                             ONSET      MIDPOINT   END                                        TRANSITION   (°C.)                                                                             (°C.)                                                                             (°C.)                               ______________________________________                                        Exotherm (minor)                                                                           126        191        .sup. 206.sup.1                            Exotherm (major)                                                                           206        213        238                                        ______________________________________                                         .sup.1 End of first exotherm merges into the second exotherm.            

The cured product is recovered from the differential scanningcalorimetry as a yellow powder and is used to prepare a nujol mull.Infrared spectrophotometric analysis of a film of the nujol mull on asodium chloride plate revealed that complete disappearance of thecyanate absorbance had occurred with retention of --CH═N-- stretchingabsorbance and appearance of a new absorbance at 1560 cm⁻¹ attributed tothe presence of the triazine ring.

D. Evaluation of the Curing Behavior of the Dicyanate ofbis(4'-hydroxyphenyl)-1,4-benzenediimine Using Optical Microscopy

A portion of the dicyanate of bis(4'-hydroxyphenyl)-1,4-benzenediiminefrom B above is placed between two glass slides and heated on a hotstage. During this heating, observations relating to changes in themorphology of the dicyanate are made at 35× magnification using a crosspolarized light source. At a heating rate of 20° C. per minute, no meltfor the dicyanate is observed up to 280° C. However, when a secondsample of the dicyanate between glass slides is introduced on to the hotstage preheated to 250° C., melt flow is observed. After melt occurred,a birefringent morphology is produced. Curing followed the melt within30 seconds with retention of birefringence in the solid. Another sampleof the dicyanate between glass slides is introduced on to the hot stagepreheated to 250° C. After melt had occurred, shear is applied to thesample by moving the top glass slide back and forth. With theapplication of shear, a shimmering fluorescence is produced. After thesample had solidified, birefringent striations are also observed whichare oriented in the same direction that the shear is applied.

E. Preparation of Cured Dicyanate ofbis(4'-Hydroxyphenyl)-1,4-benzenediimine for Thermal Mechanical Analysis

A portion (0.71 gram) of the dicyanate ofbis(4'-hydroxyphenyl)-1,4-benzenediimine from B above is placed in analuminum pan which had been coated with a mold release. The aluminum panis then put in a forced air convection type oven preheated to 250° C.Within the first minute in the oven, melt flow followed by thermosettingis observed. After 4 hours at 250° C., the oven is allowed to slowlycool to room temperature (25° C.) then the cured layer is removed fromthe pan. Optical microscopy of the cured product at 70× magnificationusing a cross polarized light source revealed extensive birefringence.Glass transition temperature and the mean linear thermal coefficient ofexpansion over the range from 35° C. to Tg are evaluated using a portionof the cured product. In this analysis, a constant probe force of 0.1Newtons and a heating rate of 10° C. per minute are used over a range of25° to 325° C. These results are reported in Table IX for both theinitial and a second heating of the same sample.

EXAMPLE 5

Preparation of a Blend of the Dicyanate ofbis(4'-Hydroxyphenyl)-1,4-benzenediimine and the Polycyanate of aDicyclopentadiene Phenolic Novolac: Evaluation of Curing Behavior UsingDifferential Scanning Calorimetry and Thermal Mechanical Analysis of theCured Blend

A portion (0.88 gram) of the dicyanate ofbis(4'-hydroxyphenyl)-1,4-benzenediimine from Example 4-B and 1.77 gramsof a 2.2 cyanate functional polycyanate of a dicyclopentadiene phenolicnovolac (uncatalyzed) from the same lot as Comparative Experiment C aremixed in an aluminum pan in a 100° C. oven. A paste is formed, a portion(15.0 milligrams) is analyzed by differential scanning calorimetry(DSC). Heating from 25° to 330° C. is completed at a rate of 10° C. perminute under a stream of nitrogen flowing at 35 cubic centimeters perminute resulting in exothermic curing. The results are reported in TableVII.

                  TABLE VII                                                       ______________________________________                                        DESCRIPTION OF                                                                              ONSET     MIDPOINT   END                                        TRANSITION    (°C.)                                                                            (°C.)                                                                             (°C.)                               ______________________________________                                        Exotherm (enthalpy =                                                                        165       217        280                                        -375 J/g)                                                                     ______________________________________                                    

The differential scanning calorimetry results may be compared with thoseshown for the neat dicyanate of bis(4'-hydroxyphenyl)-1,4-benzenediiminein Example 4-C (Table VI) and the neat polycyanate of thedicyclopentadiene phenolic novolac in Comparative Experiment C (TableVIII). When compared to the neat polycyanate of the dicyclopentadienephenolic novolac in Comparative Experiment C, the addition of thedicyanate of bis(4'-hydroxyphenyl)-1,4-benzenediimine to form thepresent blend has reduced the onset temperature to the curing exothermby 35° C. and the curing exotherm peak temperature by 79° C.

Immediately after removal of the sample for differential scanningcalorimetry, the aluminum pan is placed in a forced air, convection typeoven preheated to 250° C. Within two minutes in the oven, melt flowfollowed by thermosetting is observed. After 4 hours at 250° C., theoven is allowed to slowly cool to room temperature (25° C.) then thecured layer removed from the pan. Glass transition temperature and themean linear thermal coefficient of expansion over the range from 35° C.to Tg are evaluated using a portion of the cured product. In thisanalysis, a constant probe force of 0.1 Newtons and a heating rate of10° C. per minute are used over a range of 25° to 325° C. These resultsare reported in Table IX for both the initial and a second heating ofthe same sample.

COMPARATIVE EXPERIMENT C

Evaluation of the Curing Behavior of the Polycyanate of aDicycpentadiene Phenolic Novolac and Thermal Mechanical Analysis of theCured Polytriazine

15.0 milligrams of a commercial grade 2.2 cyanate functional polycyanateof a dicyclopentadiene phenolic novolac (uncatalyzed) is analyzed bydifferential scanning calorimetry (DSC). Heating from 25° to 330° C. iscompleted at a rate of 10° C. per minute under a stream of nitrogenflowing at 35 cubic centimeters per minute resulting in exothermiccuring. The results are reported in Table VIII.

                  TABLE VIII                                                      ______________________________________                                        DESCRIPTION OF                                                                              ONSET     MIDPOINT   END                                        TRANSITION    (°C.)                                                                            (°C.)                                                                             (°C.)                               ______________________________________                                        Exotherm (enthalpy =                                                                        200       296        315                                        -354 J/g)                                                                     ______________________________________                                    

1.93 grams of the polycyanate of a dicyclopentadiene phenolic novolac isplaced in an aluminum pan. The aluminum pan is then put in a forced airconvection type oven preheated to 250° C. After twenty minutes in theoven thermosetting is observed. After 4 hours at 250° C., the oven isallowed to slowly cool to room temperature (25° C.) then the cured layerremoved from the pan. Optical microscopy of the cured product at 70×magnification using a cross polarized light source revealed a minoramount of birefringence. Glass transition temperature and the meanlinear thermal coefficient of expansion over the range from 35° C. to Tgare evaluated using a portion of the cured product. In this analysis, aconstant probe force of 0.1 Newtons and a heating rate of 10° C. perminute are used over a range of 25° to 325° C. These results arereported in Table IX for both the initial and a second heating of thesame sample.

                                      TABLE IX                                    __________________________________________________________________________                     DESIGNATION OF SAMPLE                                                                         COMPARATIVE                                                   EXAMPLE 4-E                                                                            EXAMPLE 5                                                                            EXPERIMENT C                                 __________________________________________________________________________    Dicyanate of bis(4'-hydroxyphenyl)-                                                            100/0    33.2/66.8                                                                            0/100                                        1,4-benzenediimine/polycyanate of                                             dicyclopentadiene phenolic novolac                                            (wt. %)                                                                       Thermal Mechanical Analysis:                                                  Tg (first heat) (°C.)                                                                   285      258    240                                          Tg (second heat) (°C.)                                                                  >325     311    237                                          Mean linear coefficient of thermal                                                             53        52     58                                          expansion (first heat) (ppm/°C.)                                       Mean linear coefficient of thermal                                                             52        54     55                                          expansion (second heat) (ppm/°C.)                                      __________________________________________________________________________

EXAMPLE 6

Preparation of a Cured Polytriazine Casting from a Blend of Bisphenol ADicyanate and the Dicyanate of bis(4'-Hydroxyphenyl)-1,4-benzenediimine

A 175.0 gram portion of bisphenol A dicyanate prepared using the methodof Comparative Experiment A-A and a 25.0 gram portion of the dicyanateof bis(4'-hydroxyphenyl)-1,4-benzenediimine from Example 4-B are heatedto 145° C. to form a solution, then further heated to 150° C. and heldtherein for 10 minutes. The resulting B-staged resin solution isfiltered while hot through a heated fritted glass funnel. This solutionis then poured into a 1/8 inch mold, then placed in an oven andmaintained at 125° C. for 2 hours, 177° C. for 4 hours, 200° C. for 4hours, then 250° C. for 2 hours. The transparent, light amber coloredcasting is demolded and used to prepare test pieces which are testedusing the method of Example 1-D. The results are reported in Table X andmay be compared with those obtained for Comparative Experiment A-Breported in Table III.

                  TABLE X                                                         ______________________________________                                        MECHANICAL PROPERTY EXAMPLE 6                                                 ______________________________________                                        Barcol Hardness     51                                                        Tensile Strength (psi)                                                                            12,753                                                    Tensile Modulus (psi)                                                                             564,869                                                   Elongation (%)      3.09                                                      Flexural Strength (psi)                                                                           23,475                                                    Flexural Modulus (psi)                                                                            588,060                                                   ______________________________________                                    

EXAMPLE 7

Differential Scanning Calorimetry

The method of Example 2 is repeated using a portion (8.6 milligrams) ofthe bisphenol A dicyanate and dicyanate ofbis(4'-hydroxyphenyl)-1,4-benzenediimine blend from Example 6. Theresults from the second heating are reported in Table XI and may becompared with those reported for Comparative Experiment A-B reported inTable IV.

                  TABLE XI                                                        ______________________________________                                                   GLASS TRANSITION                                                              TEMPERATURE                                                        SAMPLE       ONSET      MIDPOINT   END                                        DESIGNATION  (°C.)                                                                             (°C.)                                                                             (°C.)                               ______________________________________                                        Example 7    255.5      263.4      277.6                                      ______________________________________                                    

EXAMPLE 8

Differential Scanning Calorimetry of Blends of the Dicyanate of4,4'-Dihydroxy-alpha-methylstilbene and Various Epoxy Resins

Blend A

A portion (0.5525 gram, 0.004 cyanate equivalent) of the dicyanate of4,4'-dihydroxy-alpha-methylstilbene from Example 1-D above, a commercialgrade diglycidyl ether of bisphenol A (179.95 epoxide equivalent weight)(0.7198 gram, 0.004 epoxide equivalent) and cobalt naphthenate (0.0013gram, 0.1% wt.) are blended then gently heated to form a homogeneoussolution.

Blend B

A portion (0.4144 gram, 0.003 cyanate equivalent ) of the dicyanate of4,4'-dihydroxy-alpha-methylstilbene from Example 1-D above, thediglycidyl ether of 4,4'-dihydroxy-alpha-methylstilbene (177.61 epoxideequivalent weight) (0.5328 gram, 0.003 epoxide equivalent) and cobaltnaphthenate (0.001 gram, 0.1% wt.) are blended then gently heated toform a homogeneous solution.

Portions (9.4 and 8.8 milligrams, respectively) of the aforementionedblends are analyzed by differential scanning calorimetry using themethod of Example 2. The results from the second heating are reported inTable XII.

                  TABLE XII                                                       ______________________________________                                                  GLASS TRANSITION                                                              TEMPERATURE                                                         SAMPLE      ONSET      MIDPOINT   END                                         DESIGNATION (°C.)                                                                             (°C.)                                                                             (°C.)                                ______________________________________                                        Example 8, Blend A                                                                        172.0      188.3      204.3                                       Example 8, Blend B                                                                        208.5      215.7      221.1                                       ______________________________________                                    

EXAMPLE 9

Differential Scanning Calorimetry of A Blend of the Dicyanate of4,4'Dihydroxy-alpha-methylstilbene and p-Vinyltoluene

A portion (0.70 gram, 70.0 % wt.) of the dicyanate of4,4'-dihydroxy-alpha-methylstilbene from Example 1-D above,p-vinyltoluene (0.30 gram, 30 % wt.) and cobalt naphthenate (0.001 gram,0.1% wt.) are blended then gently heated to form a homogeneous solution.A portion (9.5 milligrams) of the aforementioned blend is analyzed bydifferential scanning calorimetry using the method of Example 2. Theresults from the second heating are reported in Table XIII.

                  TABLE XIII                                                      ______________________________________                                                   GLASS TRANSITION                                                              TEMPERATURE                                                        SAMPLE       ONSET      MIDPOINT   END                                        DESIGNATION  (°C.)                                                                             (°C.)                                                                             (°C.)                               ______________________________________                                        Example 9    264.4      289.2      309.2                                      ______________________________________                                    

EXAMPLE 10

A. Synthesis of 4,4'-Dihydroxybenzanilide

4,4'-dihydroxybenzophenone (100.0 grams, 0.467 mole) is added to ethanol(300 milliliters) in a 1 liter Erlenmeyer flask and stirred. Afterdissolution of the 4,4'-dihydroxybenzophenone, a solution ofhydroxylamine hydrochloride (48.6 grams, 0.699 mole) and sodium acetate(57.4 grams, 0.700 mole) in deionized water (70 milliliters) is addedfollowed by an additional 100 milliliters of ethanol. This mixture isstirred and heated on a hot plate to a gentle reflux (75° C.). Afterheating for 4 hours, the solution is allowed to cool to room temperature(25° C.) with stirring and then filtered. The filter cake is washed withethanol (100 milliliters); then the total filtrant obtained (600.4grams) is concentrated to a weight of 219.2 grams by evaporation of theethanol and water. The concentrated solution is placed into a 1 literErlenmeyer flask then stirred as 600 milliliters of deionized water isadded. The addition of the deionized water induced formation of a whiteprecipitate. After thirty minutes of stirring, the mixture is filtered.The solid 4,4'-dihydroxybenzophenone oxime thus obtained weighed 98.22grams after drying. 4,4'-Dihydroxybenzophenone oxime (66.0 grams. 0.288mole) and glacial acetic acid (330 milliliters) are added to a 500milliliter round bottom flask equipped with a stirrer, water cooledcondensor, nitrogen purge and heating mantle. A catalytic amount ofp-toluenesulfonic acid (1.85 grams, 0.027 mole) is added and thereaction mixture then heated to 83° C. After heating for approximatelytwo hours, a precipitate formed and the mixture is stirred for anadditional two hours at 87° C. After this time, 25 milliliters ofdeionized water is added to the reactor and after thirty minutes, thecontents of the reactor is transferred to a 1 liter Erlenmeyer flask andmaintained therein with stirring. Immediately following the transfer,400 milliliters of deionized water is added to the flask. The mixture isstirred for forty five minutes and then filtered. The filter cake thusobtained is washed with 800 milliliters of deionized water and thendried. The resultant light beige colored solid weighed 54.82 grams.Fourier transform infrared spectrophotometric analysis of a portion ofthe product confirmed the product structure as that of4,4'-dihydroxybenzanilide. Differential scanning calorimetrydemonstrated a sharp melting point endotherm at 273° C. for the4,4'-dihydroxybenzanilide product.

B. Preparation of Dicyanate of 4,4'-Dihydroxybenzanilide

4,4'-Dihydroxybenzanilide (32.0 grams, 0.2792 hydroxyl equivalent) fromA above, cyanogen bromide (32.53 grams, 0.3071 mole) and acetone (500milliliters) are added to a reactor and maintained under a nitrogenatmosphere with stirring. The stirred solution is cooled to -5° C., thentriethylamine (28.54 grams, 0.2820 mole) is added to the reactor over a20 minute period and so as to maintain the reaction temperature at -5°to -3° C. After completion of the triethylamine addition, the reactor ismaintained at -5° to -3° C. for an additional 45 minutes followed byaddition of the reactor contents to 1 gallon of deionized water. After 2minutes of agitation the water and product mixture is filtered through afritted glass funnel to remove a cake of white crystalline product. Thefilter cake is washed with 500 milliliters of deionized water, recoveredby filtration, and again washed with 500 milliliters of deionized water.The cake recovered from a final filtration is dried at 80° C. in avacuum oven to a constant weight of 37.55 grams (96-33% isolated yield).Infrared spectrophotometric analysis of a film sample of the productconfirmed the product structure (presence of amide N-H stretching (3403cm⁻¹, sharp), presence of amide I carbonyl stretching in solid state(1681 cm⁻¹), disappearance of phenolic hydroxyl absorbance, appearanceof cyanate absorbance (2273 and 2232 cm⁻¹, sharp).

C. Evaluation of the Curing Behavior of the Dicyanate of4,4'-Dihydroxybenzanilide Using Differential Scanning Calorimetry andInfrared Spectrophotometric Analysis

A portion (11.40 milligrams) of the dicyanate of4,4'-dihydroxybenzanilide (uncatalyzed) from B above is analyzed bydifferential scanning calorimetry (DSC). Heating from 25° to 250° C. iscompleted at a rate of 10° C. per minute under a steam of nitrogenflowing at 35 cubic centimeters per minute resulting in exothermiccuring of the dicyanate. The results are reported in Table XIV.

                  TABLE XIV                                                       ______________________________________                                        DESCRIPTION OF ONSET    MIDPOINT     END                                      TRANSITION     (°C.)                                                                           (°C.) (°C.)                             ______________________________________                                        Endotherm (minor)                                                                            179      187          191                                      Exotherm (enthalpy =                                                                         191      199          209                                      -359 J/g)                                                                     ______________________________________                                    

The cured product is recovered from the differential scanningcalorimetry as a light amber colored solid and is used to prepare anujol mull. Infrared spectrophotometric analysis of a film sample of thenujol mull on a sodium chloride plate revealed that completedisappearance of the cyanate absorbance, the amide carbonyl stretch andthe amide N-H stretch had occurred with appearance of new absorbances at1743, 1654 and 1560 cm⁻¹ (1560 cm⁻¹ is attributed to the presence of thetriazine ring).

D. Evaluation of the Curing Behavior of the Dicyanate of4,4'-Dihydroxybenzanilide Using Optical Microscopy

A portion of the dicyanate of 4,4'-dihydroxybenzanilide from B above isplaced between two glass slides and heated on a hot stage. During thisheating, observations relating to changes in the morphology of thedicyanate are made at 35× magnification using a cross polarized lightsource. At a heating rate of 10° C. per minute melt flow is observed at184° C. and resulted in a birefringent texture. Curing followed the meltonce the temperature reached 187° C. On cooling to room temperature (25°C.) extensive birefringence is observed in the thermoset product.Another sample of the dicyanate between glass slides is introduced on tothe hot stage preheated to 190° C. Within one minute melt had occurredthen shear is applied to the sample by moving the top glass slide backand forth. After less than an additional 30 seconds, the sample hadsolidified and the hot stage is cooled to room temperature at a rate of10° C. per minute. At room temperature, birefringent striations are alsoobserved which are oriented in the same direction that the shear isapplied. Upon reheating of the thermoset at a rate of 10° C., thebirefringent striations remained up to 250° C. at which temperatureheating is discontinued.

E. Preparation of Cured Dicyanate of 4,4'-Dihydroxybenzanilide forThermal Mechanical Analysis

A portion (0.50 gram) of the dicyanate of 4,4'-dihydroxybenzanilide fromB above is placed in an aluminum pan. The aluminum pan is then put in aforced air convection type oven preheated to 190° C. Within the firstfive minutes in the oven, melt flow followed by thermosetting isobserved. After 5 minutes at 190° C., the oven temperature is raised to250° C. and maintained therein for four hours before the oven is allowedto slowly cool to room temperature (25° C.); then the cured layerremoved from the pan. Optical microscopy of the cured product at 70×magnification using a cross polarized light source revealed extensivebirefringence. Glass transition temperature and the mean linear thermalcoefficient of expansion over the range from 35° C. to Tg are evaluatedusing a portion of the cured product. In this analysis, a constant probeforce of 0.1 Newtons and a heating rate of 10° C. per minute are usedover a range of 25° to 325° C. These results are reported in Table XVI.

EXAMPLE 11

Preparation of a Blend of the Dicyanate of 4,4'-Dihydroxybenzanilide andthe Polycyanate of a Dicyclopentadiene Phenolic Novolac: Evaluation ofCuring Behavior Using Differential Scanning Calorimetry and ThermalMechanical Analysis of the Cured Blend

A portion (0.88 gram) of the dicyanate of 4,4'-dihydroxybenzanilide fromExample 10-B and 1.72 grams of a polycyanate of a dicyclopentadienephenolic novolac (uncatalyzed) from the same lot as ComparativeExperiment C are mixed in an aluminum pan contained in a 100° C. oven.From the paste formed, a portion (15.0 milligrams) is analyzed bydifferential scanning calorimetry (DSC). Heating from 25° to 330° C. iscompleted at a rate of 10° C. per minute under a stream of nitrogenflowing at 35 cubic centimeters per minute resulting in exothermiccuring. The results are reported in Table XV.

                  TABLE XV                                                        ______________________________________                                        DESCRIPTION OF ONSET    MIDPOINT     END                                      TRANSITION     (°C.)                                                                           (°C.) (°C.)                             ______________________________________                                        Exotherm (enthalpy =                                                                         165      212          240                                      -459 J/g)                                                                     ______________________________________                                    

The differential scanning calorimetry results may be compared with thoseshown for the neat dicyanate of 4,4'-dihydroxybenzanilide in Example10-C (Table XIV) and the neat polycyanate of the dicyclopentadienephenolic novolac in Comparative Experiment C (Table VIII). When comparedto the neat polycyanate of the dicyclopentadiene phenolic novolac inComparative Experiment C, the addition of the dicyanate of4,4'-dihydroxybenzanilide to form the present blend has reduced theonset temperature of the curing exotherm by 35° C. and the curingexotherm peak temperature by 84° C.

Immediately after removal of the sample for differential scanningcalorimetry, the aluminum pan is placed in a forced air, convection typeoven preheated to 190° C. Within fifteen minutes in the oven, melt flowfollowed by thermosetting is observed. After 3 hours at 190° C., theoven temperature is raised to 232° C. and maintained therein for twohours before the oven is allowed to slowly cool to room temperature (25°C.) then the cured layer removed from the pan. Glass transitiontemperature and the mean linear thermal coefficient of expansion overthe range from 35° C. to Tg are evaluated using a portion of the curedproduct. In this analysis, a constant probe force of 0.1 Newtons and aheating rate of 10° C. per minute are used over a range of 25° to 325°C. These results are reported in Table XVI.

COMPARATIVE EXPERIMENT D

Thermal Mechanical Analysis of the Cured Polytriazine of a Polycyanateof a Dicyclopentadiene Phenolic Novolac Use of a Different Cure Schedule

2.57 grams of the polycyanate of a dicyclopentadiene phenolic novolacfrom the same lot as Comparative Experiment C is placed in an aluminumpan. The aluminum pan is then put in a forced air convection type ovenpreheated to 190° C. After three hours at 190° C., the oven temperatureis raised to 232° C. and maintained therein for two hours before theoven is allowed to slowly cool to room temperature (25° C.); then thecured layer is removed from the pan. Optical microscopy of the curedproduct at 70× magnification using a cross polarized light sourcerevealed a minor amount of birefringence. Glass transition temperatureand the mean linear thermal coefficient of expansion over the range from35° C. to Tg are evaluated using a portion of the cured product. In thisanalysis, a constant probe force of 0.1 Newtons and a heating rate of10° C. per minute are used over a range of 25° to 325° C. These resultsare reported in Table XVI.

                                      TABLE XVI                                   __________________________________________________________________________                       DESIGNATION OF SAMPLE                                                                          COMPARATIVE                                                  EXAMPLE 10-E                                                                           EXAMPLE 11                                                                            EXPERIMENT D                              __________________________________________________________________________    Dicyanate of 4,4'-Dihydroxybenzan-                                                               100/0    33.1/66.9                                                                             0/100                                     ilide/Polycyanate of Dicyclopentadiene                                        Phenolic Novolac (wt. %)                                                      Thermal Mechanical Analysis:                                                  Tg (°C.)    242      240     239                                       Mean linear coefficient of thermal                                                                35       36      46                                       expansion (ppm/°C.)                                                    __________________________________________________________________________

EXAMPLE 12

A. Synthesis of 4'-Hydroxyphenyl-4-hydroybenzoate andbis(4'-Hydroxybenzoyl)-1,4-dihydroxybenzene

Hydroquinone (286.0 grams, 2.6 mole), p-hydroxybenzoic acid (179.4grams, 1.3 mole), diethylbenzene (52 grams) and p-toluenesulfonic acid(0.64 gram) are added to a one liter glass resin kettle reactor andheated to 200° C. with stirring under a nitrogen atmosphere flowing at arate of one liter per minute. The reactant slurry becomes an ambercolored solution once the reaction temperature reaches 165° C. Water anddiethylbenzene azeotropically distil from the reactor and are collectedin a Dean Stark trap interspersed between the reactor and a chilledwater condenser. After 45 minutes at the 200° C. reaction temperature,distillation ceases, and the reaction product is poured into an aluminumfoil tray. The resultant solid product is ground to a fine powder thenstirred in methanol (1200 milliliters) and brought to a boil. Afterboiling for 15 minutes, the slurry is filtered while still hot.Deionized water (6 liters) is added to the recovered methanol solutionand the resultant white precipitate is recovered by filtration. Theprecipitate is redissolved in stirred, boiling methanol (1200milliliters), then reprecipitated via the addition of deionized water (6liters). The resultant white precipitate recovered by filtration isdissolved a third time in stirred, boiling methanol (1000 milliliters),then the solution cooled to room temperature (25° C.) and filtered.Reprecipitation is completed by addition of the filtered solution todeionized water (5 liters). The white precipitate is recovered byfiltration then dried under vacuum for 12 hours at 90° C. to a constantweight of 125.1 grams. Fourier transform infrared spectrophotometricanalysis of a potassium chloride pellet of the product and high pressureliquid chromatographic analysis confirm the product structure for4'-hydroxyphenyl-4-hydroxybenzoate. Differential scanning calorimetry ofa portion of the product (17 milligrams) heated at 10° C. per minuteunder nitrogen flowing at 35 cubic centimeters per minute reveals asharp melting point endotherm with a minimum at 246.8° C.

The product left in the funnel from the first filtration (of thepulverized solid product boiled in 200 milliliters of methanol) isstirred in methanol (500 milliliters) and brought to a boil. Afterboiling for 15 minutes, the slurry is filtered while still hot. Thewhite product recovered on the filter is dried under vacuum for 12 hoursat 90° C. to a constant weight of 31.8 grams. Fourier transform infraredspectrophotometric analysis of a potassium chloride pellet of theproduct confirms the product structure forbis(4'-hydroxybenzoyl)-1,4-dihydroxybenzene. Differential scanningcalorimetry of a portion of the product (23.5 milligrams) heated at 10°C. per minute under nitrogen flowing at 35 cubic centimeters per minutereveals a sharp melting point endotherm with a minimum at 332.3° C.

B. Preparation of Dicyanate of 4'-Hydroxyphenyl-4-hydroxybenzoate

4'-Hydroxyphenyl-4-hydroxybenzoate (11.51 grams, 0.10 hydroxylequivalents) from A above, cyanogen bromide (11.12 grams, 0.105 moles)and acetone (350 milliliters) are added to a reactor and maintainedunder a nitrogen atmosphere with stirring. The stirred solution iscooled to -2° C., then triethylamine (10.22 grams, 0.101 mole) is addedto the reactor over a ten minute period and so as to maintain thereaction temperature at -3° to 0° C. After completion of thetriethylamine addition, the reactor is maintained at -2° to 0° C. for anadditional 45 minutes followed by addition of the reactor contents todeionized water (3 liters). After 2 minutes, the water and productmixture is filtered through a fritted glass funnel and the resultantcake of white powder is washed by slurrying into 300 milliliters ofdeionized water. A second filtration recovered the white powder which isagain washed by slurrying into 300 milliliters of deionized water. Athird filtration recovered the white powder which is then dried in avacuum oven at 80° C. and 1 mm Hg to a constant weight of 13.8 grams.Fourier transform infrared spectrophotometric analysis of a potassiumbromide pellet of product confirmed the product structure (disappearanceof phenolic hydroxyl absorbance, appearance of cyanate absorbance (2234and 2273 cm⁻¹, (sharp)).

C. Evaluation of the Curing Behavior of the Dicyanate of4'-Hydroxyphenyl-4-hydroxybenzoate using Differential ScanningCalorimetry

A portion (8.80 milligrams) of the dicyanate of4'-hydroxyphenyl-4-hydroxybenzoate from B above is analyzed bydifferential scanning calorimetry. A first heating from 30° to 300° C.is completed at a rate of 10° C. per minute under a stream of nitrogenflowing at 35 cubic centimeters per minute resulting in exothermiccuring of the dicyanate. The results are given in Table XVII. Similarly,a second heating is completed, with no glass transition temperature orany other thermal event being detected between the 30° to 300° C. rangeof the analysis.

                  TABLE XVII                                                      ______________________________________                                        DESCRIPTION ONSET      MIDPOINT   END                                         OF TRANSITION                                                                             (°C.)                                                                             (°C.)                                                                             (°C.)                                ______________________________________                                        Endotherm   134        138        145                                         (enthalpy =                                                                   82.2 J/g)                                                                     Exotherm    178        228        286                                         (enthalpy =                                                                   -423.6 J/g)                                                                   ______________________________________                                    

D. Characterization of the Dicyanate of4'-Hydroxyphenyl-4-hydroxybenzoate for Liquid Crystallinity and CuringBehavior Using Optical Microscopy

A portion of the dicyanate of 4'-hydroxyphenyl-4-hydroxybenzoate from Babove is placed between two glass slides and heated from 25° to 300° C.on a hot stage at a rate of 10° C. per minute, During this heating,observations relating to changes in the morphology of the dicyanate aremade at 35× magnification using a cross polarized light source, Theresults are given in Table XVIII,

                  TABLE XVIII                                                     ______________________________________                                        OBSERVED TRANSITION                                                           TEMPERATURES (°C.)                                                                      COMMENTS                                                     ______________________________________                                         25              Immobile crystals.                                           131              Birefringent fluid, appears as                                                crystals dispersed in fluid.                                 137              Isotropization complete.                                     202              Viscosity increases,                                                          birefringent, stir opalescent,                                                nematic fluid.                                               213              Almost solid.                                                222              Thermosets with nematic texture.                             300              Unchanged from observation at                                                 222° C.                                               ______________________________________                                    

EXAMPLE 13

A. Preparation of Dicyanate ofbis(4'-Hydroxybenzoyl)-1,4-dihydroxybenzene

bis(4'-Hydroxybenzoyl)-1,4-dihydroxybenzene (17.52 grams, 0.10 hydroxylequivalents) from Example 12-A, cyanogen bromide (11.12 grams, 0.105moles) and acetone (500 milliliters) are added to a reactor andmaintained under a nitrogen atmosphere with stirring. The stirredsolution is cooled to -2° C., then triethylamine (10.22 grams, 0.101mole) is added to the reactor over a ten minute period and so as tomaintain the reaction temperature at 0° to 2° C. After completion of thetriethylamine addition, the reactor is maintained at -1° to 1° C. for anadditional 45 minutes followed by addition of the reactor contents todeionized water (3.5 liters). After 2 minutes, the water and productmixture is filtered through a fritted glass funnel and the resultantcake of white powder is washed by slurrying into 300 milliliters ofdeionized water. A second filtration recovered the white powder which isagain washed by slurrying into 300 milliliters of deionzed water. Athird filtration recovered the white powder which is then dried in avacuum oven at 80° C. and 1 mm Hg to a constant weight of 19.3 grams.Fourier transform infrared spectrophotometric analysis of a potassiumbromide pellet of product confirmed the product structure (disappearanceof phenolic hydroxyl absorbance, appearance of cyanate absorbance (2260and 2293 cm⁻¹, (sharp)).

B. Evaluation of the Curing Behavior of the Dicyanate ofbis(4'-Hydroxybenzoyl)-1,4-dihydroxybenzene Using Differential ScanningCalorimetry

A portion (10.0 milligrams) of the dicyanate ofbis(4'-hydroxybenzoyl)-1,4-dihydroxybenzene from A above is analyzed bydifferential scanning calorimetry. A first heating from 30° to 300° C.is completed at a rate of 10° C. per minute under a stream of nitrogenflowing at 35 cubic centimeters per minute resulting in exothermiccuring of the dicyanate. The results are given in Table XVIX. Similarly,a second heating is completed with the results given in Table XX.

                  TABLE XVIX                                                      ______________________________________                                        DESCRIPTION ONSET      MIDPOINT   END                                         OF TRANSITION                                                                             (°C.)                                                                             (°C.)                                                                             (°C.)                                ______________________________________                                        Endotherm    90         99        111                                         (enthalpy =                                                                   14.6 J/g)                                                                     Exotherm    .sup. 118.sup.1                                                                          167        277                                         (enthalpy =                                                                   -285.7 J/g)                                                                   ______________________________________                                         .sup.1 Point of first increase above baseline, sharp exothermic peak          begins at 145.8° C.                                               

                  TABLE XX                                                        ______________________________________                                                   GLASS TRANSITION                                                              TEMPERATURE                                                        SAMPLE       ONSET      MIDPOINT   END                                        DESIGNATION  (°C.)                                                                             (°C.)                                                                             (°C.)                               ______________________________________                                        Example 12-B 178.1      184.5      192.3                                      ______________________________________                                    

C. Characterization of the Dicyanate ofbis(4'-Hydroxybenzoyl)-1,4-dihydroxybenzene for Liquid Crystallinity andCuring Behavior Using Optical Microscopy

A portion of the dicyanate ofbis(4'-hydroxybenzoyl)-1,4-dihydroxybenzene from A above is placedbetween two glass slides and heated from 25° to 300° C. on a hot stageat a rate of 10° C. per minute. During this heating, observationsrelating to changes in the morphology of the dicyanate are made at 35×magnification using a cross polarized light source. The results aregiven in Table XXI.

                  TABLE XXI                                                       ______________________________________                                        OBSERVED TRANSITION                                                           TEMPERATURES (°C.)                                                                      COMMENTS                                                     ______________________________________                                         25              Immobile crystals.                                           140              Birefringent crystalline solid                                                softens.                                                     153              Birefringent solid, no longer                                                 softened.                                                    300              Unchanged from observation at                                                 153° C.                                               ______________________________________                                    

A second sample of the dicyanate between glass slides is introduced onto the hot stage preheated to 200° C. After seven seconds melt flow to aliquid crystalline fluid having a nematic texture is observed. After 40seconds shear is applied to the sample by moving the top glass slideback and forth. With the application of shear, birefringent striationsare observed which are oriented in the direction perpendicular to thedirection that shear is applied. After 70 seconds, the sample solidifieswith retention of the oriented birefringent striations.

EXAMPLE 14

Preparation of a Cured Polytriazine Casting from the Dicyanate of4'-Hydroxyphenyl-4-hydroxybenzoate

An eleven gram portion of a dicyanate of4'-hydroxyphenyl-4-hydroxybenzoate prepared using the method of Example12-B is placed in a beaker then put in a forced air convection type ovenpreheated to 160° C. Nine minutes later, after melting is complete, theresin is degassed using a vacuum bell jar then poured into a mold whichis preheated to 160° C. and has the following dimensions: 4.0×0.75×0.125inches (102×19.0×3.17 mm). The filled mold is placed in an oven andmaintained at 160° C. for 2 hours. After this time, the oven temperatureis increased 20° C. per hour until a temperature of 245° C. is achieved.The 245° C. temperature is then maintained for 3 hours followed bygradual cooling to room temperature (23° C.). The opaque, yellow coloredcasting is demolded and tested for flexural properties using the methodof Example 1-D. The flexural strength and modulus thus obtained are17,752 and 430,625 psi, respectively. Differential scanning calorimetryof a portion (30.0 milligrams) of the casting reveals a glass transitiontemperature with an onset at 245.2° C., a midpoint at 251.5° C. and anend at 255.1° C. Optical microscopy of the casting at 35× magnificationusing a cross polarized light source reveals large (>25 microns) smecticdomains.

EXAMPLE 15

A. Preparation of an Injection Molded Cured

Polytriazine Casting from the Dicyanate of4'-Hydroxyphenyl-4-hydroxybenzoate

An eight gram portion of a dicyanate of4'-hydroxyphenyl-4-hydroxybenzoate from Example 12-B is placed in abeaker then put in a forced air convection type oven preheated to 160°C. Eleven minutes later, after melting is complete, the resin isdegassed using a vacuum bell jar then poured into the reservoir of aninjection molder which is preheated to 160° C. After twelve minutes inthe reservoir, the resin begins to develop opacity. After seventeenminutes in the reservoir, fibers can be drawn from the molten resin witha cold spatula. After nineteen minutes in the reservoir the resin isinjected through a 0.02 inch (0.508 mm) rectangular flow gate into amold preheated to 130° C. and having the following dimensions:3.0×0.50×0.125 inches (76.2×12.7×3.17 mm). The filled mold is placed inan oven and maintained at 130° C. for 2 hours. After this time the oventemperature is increased 10° C. per hour until a temperature of 160° C.is achieved then 20° C. per hour until a temperature of 245° C. isachieved. The 245° C. temperature is then maintained for 3 hoursfollowed by gradual cooling to room temperature (23° C.). The castingwhich possess both a translucent and an opalescent phase, is demoldedand tested for flexural properties using the method of Example 1-D. Theflexural strength and modulus thus obtained are 14,773 and 507,613 psi.respectively. Differential scanning calorimetry of a portion (30.0milligrams) of the casting reveals a glass transition temperature withan onset at 246.9° C., a midpoint at 251.2° C. and an end at 256.1° C.Optical microscopy of the casting at 35× magnification using a crosspolarized light source reveals liquid crystal textures. Opticalmicroscopy at 35× magnification using a cross polarized light source ofa sample of the 160° C. resin which is removed from the reservoir at thetime of injection into the mold and placed between two glass slides onthe hot stage preheated to 160° C. reveals the presence of liquidcrystal texture. At this time, shear is applied to the sample by movingthe top glass slide back and forth. With the application of shear,orientation is observed in the direction perpendicular to the directionthat shear is applied. When cooled to 140° C., shear is again applied tothe barely mobile resin and results in orientation both parallel andtransverse to the direction that shear is applied.

B. Thermal Mechanical Analysis of the Injection Molded CuredPolytriazine Casting of the Dicyanate of4'-Hydroxyphenyl-4-Hydroxybenzoate

Cubes measuring 0.125 inch (3.17 mm) are cut from the injection moldedcasting prepared in A above then used in thermal mechanical analysis. Inthis analysis, a constant probe force of 0.1 Newtons and a heating rateof 5° C. per minute is used over a range of 40° to 225° C. The meanlinear coefficients of thermal expansion obtained from the analyses areas follows: 97 ppm/°C. for the z coordinate (surface of the casting), 35ppm/°C. for the y coordinate (flow direction) and 91 ppm/°C. for the xdirection (transverse to the flow direction). The substantially lowermean linear coefficient of thermal expansion in the direction of the ycoordinate demonstrates the anisotropy which can be produced byprocessing methods that induce shear, such as injection molding.

What is claimed is:
 1. A polycyanate or polycyanamide compositioncontaining one or more rodlike mesogenic moieties represented by thefollowing Formulas I, II, III or IV ##STR34## wherein at least about 80percent of the --A-- linkages, the direct bond in Formula III and the Ygroups are in the para position with respect to each other; each Y isindependently a --O--C.tbd.N or a --NR¹ --C.tbd.N group; each A inFormula II when p is 1 is independently --CR¹ ═CR¹ --, --C.tbd.C--,--N═N--,--CR¹ ═N--, --NR¹ --CO--, --CR¹ ═N--N═CR¹ --, --CR¹ ═CR¹ --CO--,--CO--NR¹ --, --CO--CR¹ ═CR¹ --, --CR¹ ═CR¹ --O--CO--(CH₂)_(n') --,--N═CR¹ --, --(CH₂)_(n) '--CO--O--CR¹ ═CR¹ --, --CR¹ ═CR¹ --O--CO--,--CO--O--CR¹ ═CR¹ --, --CO--O--N═CR¹ --, --CR¹ ═N--O-- CO--, --CR¹ ═CR¹--CO--O--, --CO--S--, --O--CO--CR¹ ═CR¹, --CR¹ ═CR¹ --CO--O--(CH₂)_(n)'--, --S--CO--, --(CH₂)_(n) '--O--CO--CR¹ ═CR¹ --, --CHR¹ --CHR¹--CO--O--, --O--CO--CHR¹ --CHR¹ --, --C.tbd.C--C.tbd.C--, --CR¹ ═CR¹--CR¹ ═CR¹ --, --CO--NR¹ --NR¹ --CO--, ##STR35## and in Formulas I, IVand in Formula II when p is other than 1 or when p is 1 and Y is --NR¹--C.tbd.N, each A is independently selected from the same group as aboveplus --O--CO-- and --CO--O--; A' is a divalent hydrocarbyl group havingfrom 1 to about 10 carbon atoms; each A" is independently an alkylenegroup having from 1 to about 10 carbon atoms, a direct bond, --O--,--CO--, --S--, --S--S--, --SO--, --SO₂ -- or --O--CO--O--; each A¹ isindependently a --CO--, --O--CO--, --CO--O--, --CO--NR¹ --, or --NR¹--CO-- group; each R is independently hydrogen or a hydrocarbyl orhydrocarbyloxy group having from 1 to about 10 carbon atoms, a halogenatom, a nitro group, a nitrile group, a phenyl group or a --CO--R¹group; each R¹ is independently hydrogen or a hydrocarbyl group having 1to about 3 carbon atoms; v has a value of one to two; n has a value ofzero or one; n' has a value from 1 to about 6; p has a value from 1 toabout 30; and wherein the aromatic rings can also contain one or moreheteroatoms selected from N, O, or S; with the proviso that saidpolycyanate or polycyanamide composition cannot be4,4'-dicyanatostilbene, 4,4'-dicyanamidoazobenzene,4,4'-dicyanamidobenzanilide, 4,4'-dicyanamidophenyl benzoate, dicyanatesof the diphenol esters of terephthaloyl chloride and bisphenol A,4,4'-dihydroxydiphenyl, and dicyanates represented by the followingformulas ##STR36## wherein Ar is an aromatic radical selected from thegroup consisting of 1,4'-benzene, 1,4-naphthalene, 1,5-naphthalene,2,6-naphthalene, 2,7-naphthalene, 4,4'-biphenyl or 4,4'-diphenylalkyleneradicals and can possess any nonactive hydrogen-containingsubstituent(s) which do not remove mesogenicity.
 2. A polycyanate orpolycyanamide composition of claim 1 wherein said polycyanate orpolycyanamide is the dicyanate of 4,4'-dihydroxy-α-methylstilbene, thedicyanate of bis(4'-hydroxyphenyl)-1,4-benzenediimine, the dicyanate of4,4'-dihydroxybenzanilide, the dicyanate of4'-hydroxyphenyl-4-hydroxybenzoate, the dicyanate ofbis(4'-hydroxybenzoyl)-1,4-dihydroxybenzene, or any combination thereof.